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Search indexed bioRxiv preprints in genomics, neuroscience, cell biology and bioinformatics. Read source abstracts and check manuscript versions; preprints are not peer reviewed.

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bioRxiv2018

Chicory demonstrates substantial water uptake from below 2 m, but still did not escape topsoil drought

AimsDeep-rooted agricultural crops can potentially utilize deep water pools and thus reduce periods where growth is water limited. Chicory (Cichorium intybus L.) is known to be deep-rooted, but the contribution of deep roots to water uptake under well-watered and drought conditions by the deep root system has not been studied. The aim of this study was to investigate whether chicory could reach 3 m depth within a growing season and demonstrate significant water uptake from the deeper part of the root zone. MethodsWe tested if chicory exposed to either topsoil drought or resource competition from the shallow-rooted species ryegrass (Lolium perenne L.) and black medic (Medicago lupulina L.) would increase deep water uptake in compensation for reduced topsoil water uptake. We grew chicory in 4 m deep soil filled rhizotrons and found that the roots reached 3 m depth within a growing season. ResultsWater uptake from below 1.7 m depth in 2016 and 2.3 m depth in 2017 contributed significantly to chicory water use. However, neither drought nor intercropping increased the deep water uptake. ConclusionChicory benefits from being deep-rooted during drought events, yet deep water uptake cannot compensate for the reduced topsoil water uptake during drought.

plant biology↗

bioRxiv2018

A regulatory module controlling stress-induced cell cycle arrest in Arabidopsis

Cell cycle arrest is an active response to stresses that enables organisms to survive under fluctuating environmental conditions. While signalling pathways that inhibit cell cycle progression have been elucidated, the putative core module orchestrating cell cycle arrest in response to various stresses is still elusive. Here we report that in Arabidopsis thaliana, the NAC-type transcription factors ANAC044 and ANAC085 are required for DNA damage-induced G2 arrest. Under genotoxic stress conditions, ANAC044 and ANAC085 enhance protein accumulation of the R1R2R3-type Myb transcription factor (Rep-MYB), which represses G2/M-specific genes. ANAC044/ANAC085-dependent accumulation of Rep-MYB and cell cycle arrest are also observed in the response to heat stress that causes G2 arrest, but not to osmotic stress that retards G1 progression. These results suggest that plants deploy the ANAC044/ANAC085-mediated signalling module as a hub which perceives distinct stress signals and leads to G2 arrest.

plant biology↗

bioRxiv2018

Clonal seeds in hybrid rice using CRISPR/Cas9

Heterosis, the observation that first generation hybrids outcompete the parental lines, is widely used in increasing the productivity and yield of agricultural crops1,2. However, heterosis is lost in the following generations because of genetic segregation. In addition, the high cost of hybrid seed production hinders the application of heterosis in many crops. Clonal reproduction through seeds could be revolutionary for agriculture by allowing self-propagation of F1 hybrids3,4. Here we show that heterozygosity of F1 hybrid rice can be fixed and thus propagated without additional crossing. First, we showed that multiplex editing of three key meiotic genes5,6 in hybrid rice leads to the production of clonal diploid gametes and tetraploid seeds. Next, editing of the MATRILINEAL (MTL) gene that involved in fertilization7,8 results in the induction of haploid seeds in hybrid rice. By simultaneous editing of these four endogenous genes in hybrid rice using the CRISPR/Cas9 system, we obtained in one generation plants able to propagate clonally through seeds. This opens the possibility to fix heterozygosity of hybrid varieties in food crops.

plant biology↗

bioRxiv2018

Anchorene is an endogenous diapocarotenoid required for anchor root formation in Arabidopsis

Arabidopsis root development is predicted to be regulated by yet unidentified carotenoid-derived metabolite(s). In this work, we screened known and putative carotenoid cleavage products and identified anchorene, a predicted carotenoid-derived dialdehyde (diapocarotenoid) that triggers anchor root development. Anchor roots are the least characterized type of root in Arabidopsis. They form at the root-shoot junction, particularly upon damage to the root apical meristem. Using Arabidopsis reporter lines, mutants and chemical inhibitors, we show that anchor roots originate from pericycle cells and that the development of this root type is auxin-dependent and requires carotenoid biosynthesis. Transcriptome analysis and treatment of auxin-reporter lines indicate that anchorene triggers anchor root development by modulating auxin homeostasis. Exogenous application of anchorene restored anchor root development in carotenoid-deficient plants, indicating that this compound is the carotenoid-derived signal required for anchor root development. Chemical modifications of anchorene led to a loss of anchor root promoting activity, suggesting that this compound is highly specific. Furthermore, we demonstrate by LC-MS analysis that anchorene is a natural, endogenous Arabidopsis metabolite. Taken together, our work reveals a new member of the family of carotenoid-derived regulatory metabolites and hormones.\n\nSignificanceUnknown carotenoid-derived compounds are predicted to regulate different aspects of plant development. Here, we characterize the development of anchor roots, the least characterized root type in Arabidopsis, and show that this process depends on auxin and requires a carotenoid-derived metabolite. We identified a presumed carotenoid-derivative, anchorene, as the likely, specific signal involved in anchor root formation. We further show that anchorene is a natural metabolite that occurs in Arabidopsis. Based on the analysis of auxin reporter lines and transcriptome data, we provide evidence that anchorene triggers the growth of anchor roots by modulating auxin homeostasis. Taken together, our work identifies a novel carotenoid-derived growth regulator with a specific developmental function.

plant biology↗

bioRxiv2018

A framework for genomics-informed ecophysiological modeling in plants

Dynamic process-based plant models capture complex physiological response across time, carrying the potential to extend simulations out to novel environments and lend mechanistic insight to observed phenotypes. Despite the translational opportunities for varietal crop improvement that could be unlocked by linking natural genetic variation to first-principles based modeling, these models are challenging to apply to large populations of related individuals. Here we use a combination of model development, experimental evaluation, and genomic prediction in Brassica rapa L. to set the stage for future large-scale process-based modeling of intra-specific variation. We develop a new canopy growth sub-model for B. rapa within the process-based model Terrestrial Regional Ecosystem Exchange Simulator (TREES), test input parameters for feasibility of direct estimation with observed phenotypes across cultivated morphotypes and indirect estimation using genomic prediction on a Recombinant Inbred Line population, and explore model performance on an in silico population under non-stressed and mild water stressed conditions. We find evidence that the updated whole plant model has capacity to distill genotype by environment interaction (G x E) into tractable components. The framework presented offers a means to link genetic variation with environment-modulated plant response and serves as a stepping stone towards large-scale prediction of un-phenotyped, genetically-related individuals under un-tested environmental scenarios.

plant biology↗

bioRxiv2018

Dicer-like 5 deficiency confers temperature-sensitive male sterility in maize

Small RNAs play important roles during plant development by regulating transcript levels of target mRNAs, maintaining genome integrity, and reinforcing DNA methylation. Dicer-like 5 (Dcl5) is proposed to be responsible for precise slicing in many monocots to generate diverse 24-nt phased, secondary small interfering RNAs (phasiRNAs), which are exceptionally abundant in meiotic anthers of diverse flowering plants. The importance and functions of these phasiRNAs remain unclear. Here, we characterized several mutants of dcl5, including alleles generated by the Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) Cas9 system and a transposon-disrupted allele. We report that dcl5 mutants have few or no 24-nt phasiRNAs, develop short anthers with defective tapetal cells, and exhibit temperature-sensitive male fertility. We propose that DCL5 and 24-nt phasiRNAs are critical for fertility under growth regimes for optimal yield.

plant biology↗

bioRxiv2018

Reference genes for RT-qPCR normalisation in different tissues, developmental stages and stress conditions of Hypericum perforatum

AbstactHypericum perforatum is a widely known medicinal herb used mostly as a remedy for depression because of its abundant secondary metabolites. Quantitative real-time PCR (qRT-PCR) is an optimized method for the efficient and reliable quantification of gene expression studies. In general, reference genes are used in qRT-PCR analysis because of their known or suspected housekeeping roles. However, their expression level cannot be assumed to remain stable under all possible experimental conditions. Thus, the identification of high quality reference genes is very necessary for the interpretation of qRT-PCR data. In this study, we investigated the expression of fourteen candidate genes, including nine housekeeping genes and five potential candidate genes. Additionally, the HpHYP1 gene, belonging to the PR-10 family associated with stress control, was used for validation of the candidate reference genes. Three programs were applied to evaluate the gene expression stability across four different plant tissues, three developmental stages and a set of abiotic stress and hormonal treatments. The candidate genes showed a wide range of Ct values in all samples, indicating that they are differentially expressed. Integrating all of the algorithms and evaluations, ACT2 and TUB-{beta} were the most stable combination overall and for different developmental stages samples. Moreover, ACT2 and EF1- were considered to be the two most applicable reference genes for different tissues and for stress samples. Majority of the conventional housekeeping genes exhibited better than the potential reference genes. The obtained results will contribute to improving credibility of standardization and quantification of transcription levels in future expression research of H. perforatum.

plant biology↗

bioRxiv2018

QTL mapping of leaf angle on eight nodes in maize enable the optimize canopy by differential operating of leaf angle at different levels of plant

Leaf angle (LA) is one of the most important canopy architecture related traits of maize (Zea mays L.). Currently, there is an urgent need to elucidate the genetic mechanism of LA at canopy-wide levels for optimizing dense-planting canopy architecture. In present study, one RIL population derived from two parent lines which show distinct plant architecture was used to perform QTL mapping for LA at eight leaves below the tassel under three environments. Dozens of QTL for LA at eight leaves were identified, which were mapped on all maize chromosomes except for the tenth chromosome. Among them, there were nine common QTL as they were identified for LA more than 1 leaves or in two or three environments. And individual QTL could explain 1.29% - 20.14% of the phenotypic variation and affect LA of 1-8 leaves, including qLA5.1 affected LA of all eight leaves, qLA3.1 affected LA of the upper leaves (1stLA to 4thLA), and qLA9.1 could affect LA of the lower leaves (5thLA to 8thLA). Furthermore, the results indicated that the genetic architecture of LA at eight leaves was different. Specifically, 8thLA was mainly affected by major and minor QTL; 1stLA, 4thLA and 5thLA were affected by epistatic interactions beside major and minor QTL; while the other four LAs were simultaneously affected by major QTL, minor QTL, epistatic interactions and environments. These results provide a comprehensive understanding of genetic basis of LA at canopy-wide levels, which will be beneficial to design ideal plant architecture under dense planting in maize. Author contribution statementJ. L. and D. T. designed and supervised the study, D. T., Z.C., J.N., Q.J., P.L., L.W., J.Z., C.L. performed the phenotypic data collection. D. T. analyzed the data and drafted the manuscript, D. T. and Z.C. revised and finalized the manuscript. All the authors read and approved the manuscript. Key messageDozens of QTL for leaf angle of eight consecutive leaves were identified in the RIL population across three environments, providing the information that optimization of canopy architecture at various canopy levels.

plant biology↗

bioRxiv2018

Novel, economically important semi-dwarf and early mutants: Selection and development from Improved White Ponni Rice (Oryza sativa L.)

Rice variety, Improved White Ponni is a medium duration crop, but highly susceptible to lodging impacting maximum yield losses. The present investigation aimed to identify early and early semi-dwarf mutants in Improved White Ponni by inducing variations using gamma rays without altering its native grain quality traits. Seeds were treated with various doses of after fixation of the LD50 value of gamma radiation and reported that most of the traits exhibit variations in the mutants at various levels of irradiation. The selection for earliness and dwarf plant height was imposed in M2 and it was confirmed by evaluation of M3 generation. Apart from semi-dwarf early mutants, high tillering habit, narrow rolled leaf, upper albino leaf and grassy stunt and extreme dwarf mutants were also identified. Characterization of mutants using already reported genic and linked microsatellite markers associated with semi-dwarfism and earliness resulted that PIC value ranges between 0.037 and 0.949 with an average of 0.382. Single marker analysis revealed that RM302 and RM310 on chromosome 1 and 8 had exhibited an association with the traits plant height, culm and internodal lengths. Of these gene-specific markers, GA20Oxi_1 and GA20Oxi_2 have shown polymorphism among mutants. GA20Oxi_2 showed null alleles in the dwarf mutants and this clearly emphasized that there are some base deletions exists in the region of exon 2 of sd1 region. GA3 response study shown that identified mutants were GA3 responsive except IWP 11-2, IWP 48-2, IWP 50-11 and IWP 33-2 which showed very low responsive. Agar plate assay revealed that, IWP 50-11, IWP 33-2, IWP 43-1, IWP 47-2 and IWP 18-1 had low production of - amylase. Scanning electron microscope examination on confirmed mutants exhibited larger cell size and a lesser number of cells per unit area than the wild-type which shows that these mutants are defective in GA mediated pathway.

plant biology↗

bioRxiv2018

Functional characterization of Arabidopsis ARGONAUTE 3 in reproductive tissue

Arabidopsis encodes ten ARGONAUTE (AGO) effectors of RNA silencing, canonically loaded with either 21-22nt small RNAs (sRNA) to mediate post-transcriptional-gene-silencing (PTGS) or 24nt sRNAs to promote RNA-directed-DNA-methylation. Using full-locus constructs, we characterized the expression, biochemical properties, and possible modes of action of AGO3. Although AGO3 arose from a recent duplication at the AGO2 locus, their expression differs drastically, with AGO2 being expressed in both male and female gametes whereas AGO3 accumulates in aerial vascular terminations and specifically in chalazal seed integuments. Accordingly, AGO3 down-regulation alters gene expression in siliques. Similar to AGO2, AGO3 binds sRNAs with a strong 5-adenosine bias, but unlike most Arabidopsis AGOs - AGO2 included - it binds efficiently both 24nt and 21nt sRNAs. AGO3 immunoprecipitation experiments in siliques revealed that these sRNAs mostly correspond to genes and intergenic regions. in a manner reflecting their respective accumulation from their loci-of-origin. AGO3 localizes to the cytoplasm and co-fractionates with polysomes to possibly mediate PTGS via translation inhibition.\n\nSignificance statementThe regulation of gene expression by small RNAs is key for proper plant development and defense. Here, we characterize Arabidopsis AGO3 expression pattern, microRNA regulation and biochemical properties during sexual reproduction.

plant biology↗

bioRxiv2018

Analysis of small RNA silencing in Zymoseptoria tritici - wheat interactions

Cross-kingdom small RNA (sRNA) silencing has recently emerged as a mechanism facilitating fungal colonization and disease development. Here we characterized RNAi pathways in Zymoseptoria tritici, a major fungal pathogen of wheat, and assessed their contribution to pathogenesis. Computational analysis of fungal sRNA and host mRNA sequencing datasets was used to define the global sRNA populations in Z. tritici and predict their mRNA targets in wheat. 389 in planta-induced sRNA loci were identified. sRNAs generated from some of these loci were predicted to target wheat mRNAs including those potentially involved in pathogen defense. However, molecular approaches failed to validate targeting of selected wheat mRNAs by fungal sRNAs. Mutant strains of Z. tritici carrying deletions of genes encoding key components of RNAi such as Dicer-like (DCL) and Argounate (AGO) proteins were generated, and virulence bioassays suggested that these are dispensable for full infection of wheat. Nonetheless, our results did suggest the existence of non-canonical DCL-independent pathway(s) for sRNA biogenesis in Z. tritici. dsRNA targeting essential fungal genes applied in vitro or generated from an RNA virus vector in planta in a procedure known as HIGS (Host-Induced Gene Silencing) was ineffective in preventing Z. tritici growth or disease. We also demonstrated that Z. tritici is incapable of dsRNA uptake. Collectively, our data suggest that RNAi approaches for gene function analyses in this fungal species and potentially also as a control measure may not be as effective as has been demonstrated for some other plant pathogenic fungi.

plant biology↗

bioRxiv2018

Decoys provide a scalable platform for the genetic analysis of plant E3 ubiquitin ligases that regulate circadian clock function

The circadian clock in all eukaryotes relies on the regulated degradation of clock proteins to maintain 24-hour rhythmicity. Despite this knowledge, we know very few of the components that mediate degradation of proteins to control clock function. This is likely due to high levels of gene duplication and functional redundancy within plant E3 ubiquitin ligase gene families. In order to overcome this issue and discover E3 ubiquitin ligases that control circadian clock function, we generated a library of transgenic Arabidopsis lines expressing dominant-negative \"decoy\" E3 ubiquitin ligases. We determined their effects on the plant circadian clock and identified dozens of new potential regulators of circadian clock function. To demonstrate the potency of the decoy screening methodology to overcome genetic redundancy and identify bona fide clock regulators, we performed follow-up studies on PUB59 and PUB60. Using knock-out studies, we show that they redundantly control circadian clock period by regulating gene splicing. Furthermore, we confirm that they are part of a conserved protein complex that mediates splicing in eukaryotes. This work demonstrates the viability of E3 ubiquitin ligase decoys as a scalable screening platform to overcome traditional genetic challenges and discover E3 ubiquitin ligases that regulate plant developmental processes.

plant biology↗

bioRxiv2018

Precision phenotyping reveals novel loci for quantitative resistance to septoria tritici blotch in European winter wheat

O_LIAccurate, high-throughput phenotyping for quantitative traits is the limiting factor for progress in plant breeding. We developed automated image analysis to measure quantitative resistance to septoria tritici blotch (STB), a globally important wheat disease, enabling identification of small chromosome intervals containing plausible candidate genes for STB resistance.\nC_LIO_LI335 winter wheat cultivars were included in a replicated field experiment that experienced natural epidemic development by a highly diverse but fungicide-resistant pathogen population. More than 5.4 million automatically generated phenotypes were associated with 13,648 SNP markers to perform a GWAS.\nC_LIO_LIWe identified 26 chromosome intervals explaining 1.9-10.6% of the variance associated with four resistance traits. Seventeen of the intervals were less than 5 Mbp in size and encoded only 173 genes, including many genes associated with disease resistance. Five intervals contained four or fewer genes, providing high priority targets for functional validation. Ten chromosome intervals were not previously associated with STB resistance.\nC_LIO_LIOur experiment illustrates how high-throughput automated phenotyping can accelerate breeding for quantitative disease resistance. The SNP markers associated with these chromosome intervals can be used to recombine different forms of quantitative STB resistance that are likely to be more durable than pyramids of major resistance genes.\nC_LI

plant biology↗

bioRxiv2018

Partial-resistance against aphids in wild barley involves phloem and mesophyll-based defences

Aphids, including the bird cherry-oat aphid (Rhopalosiphum padi), are significant agricultural pests. Aphid populations are typically controlled using insecticides, but there is increasing demand for more sustainable pest management practices. The wild relative of barley, Hordeum spontaneum 5 (Hsp5) has been described as partially-resistant to R. padi. Partial-resistance is proposed to involve higher thionin and lipoxygenase gene expression. However, the underlying mechanistic processes are unknown. In this study we compared Hsp5 with a susceptible cultivar of barley (Concerto) to test the extent to which partial-resistance affects aphid fitness. We used the electrical penetration graph technique to monitor R. padi feeding patterns to elucidate the tissue location of partial-resistance factors alongside molecular and biochemical analyses to identify potential mechanisms. We show that partial-resistance in Hsp5 extends to three aphid species and is mediated by phloem/mesophyll-based factors, leading to a three-fold increase in the time aphids take to establish sustained phloem ingestion. Partial-resistance likely involves elevated expression of defence and phytohormone genes alongside altered phloem amino acid composition. Further work is required to establish the function of these traits, however this study highlights plant tissues which are important in conferring broad-spectrum partial-resistance against aphids in barley.\n\nHighlightPartial-resistance against aphids in wild barley is based in the mesophyll and vascular tissue and is potentially associated with higher basal defence gene expression and altered phloem amino acid composition.

plant biology↗

bioRxiv2018

Trichoderma asperelloides enhances local (LAR) and systemic acquired resistance (SAR) response under low nitrate nutrition in Arabidopsis

Nitrogen (N) is essential for growth, development and defense but, how low N affects defense and the role of Trichoderma in enhancing defense under low nitrate is not known. Low nitrate fed Arabidopsis plants displayed reduced growth and compromised local and systemic acquired resistance responses when infected with both avirulent and virulent Pseudomonas syringae DC3000. These responses were enhanced in the presence of Trichoderma. The mechanism of increased local and systemic acquired resistance mediated by Trichoderma involved increased N uptake and enhanced protein levels via modulation of nitrate transporter genes. The nrt2.1 mutant is compromised in local and systemic acquired resistance responses suggesting a link between enhanced N transport and defense. Enhanced N uptake was mediated by Trichoderma elicited nitric oxide (NO). Low NO producing nia1,2 mutant and nsHb+ over expressing lines were unable to induce nitrate transporters and thereby compromised defense in the presence of Trichoderma under low N suggesting a signaling role of Trichoderma elicited NO. Trichoderma also induced SA and defense gene expression under low N. The SA deficient NahG transgenic line and the npr1 mutant were also compromised in Trichoderma-mediated local and systemic acquired resistance responses. Collectively our results indicated that the mechanism of enhanced plant defense under low N mediated by Trichoderma involves NO, ROS, SA production as well as the induction of NRT and marker genes for systemic acquired resistance. One-sentence summaryTrichoderma enhances local and systemic acquired resistance under low nitrate nutrition

plant biology↗

bioRxiv2018

Evolution of metabolic novelty: a trichome-expressed invertase creates specialized metabolic diversity in wild tomato

Plants produce myriad taxonomically restricted specialized metabolites. This diversity - and our ability to correlate genotype with phenotype - makes the evolution of these ecologically and medicinally important compounds interesting and experimentally tractable. Trichomes of tomato and other nightshade family plants produce structurally diverse protective compounds termed acylsugars. While cultivated tomato (Solanum lycopersicum) accumulates strictly acylsucroses, the South American wild relative Solanum pennellii produces copious amounts of acylglucoses. Genetic, transgenic and biochemical dissection of the S. pennellii acylglucose biosynthetic pathway identified a trichome gland cell expressed invertase-like enzyme that hydrolyzes acylsucroses (Sopen03g040490). This enzyme acts on the pyranose ring-acylated acylsucroses found in the wild tomato but not the furanose ring-decorated acylsucroses of cultivated tomato. These results show that modification of the core acylsucrose biosynthetic pathway leading to loss of furanose ring acylation set the stage for co-option of a general metabolic enzyme to produce a new class of protective compounds.

plant biology↗

bioRxiv2018

VIT1-dependent Fe distribution in seeds is conserved in dicots

One third of the people suffer from iron (Fe) Fe deficiency. An underlying factor for this malnutrition is insufficient Fe intake from the diet. A major part of the human diet includes seeds of staple crops, which contain Fe that is poorly bioavailable. One reason for the low bioavailability is these seeds store Fe in cellular compartments that also contain antinutrients, such as phytate. Thus, several studies focused on decreasing phytate concentrations. As an alternative approach to increase bioavailable Fe, Fe reserves might be directed to cellular compartments such as plastids that are free of phytate. Previous studies indicated that Fe reserves can be relocalized inside the seed to the desired compartment by genetic modification, provided that a suitable iron transporter protein is used. However, to the best of our knowledge, a Fe transporter localizing to plastids have not been identified in seeds to date. To discover novel Fe transporters, we screened Fe patterns in seeds of distinct plant lineages, hypothesizing Fe hyperaccumulating sites would indicate Fe transporter presence. To this end, metal localizations in seeds of more than twenty species were investigated using histochemical or X-ray based techniques. Results showed that in Rosids, the largest clade of eudicots, Fe reserves were primarily confined in the embryo part of the seeds. Furthermore, inside the embryos, Fe was enriched in the endodermal cell layer, a well-known feature that is mediated by vacuolar Fe transporter, VIT1 in model plant Arabidopsis thaliana. This enrichment was well conserved in and beyond Rosid species. Finally, a few seeds showed novel Fe patterns, including Carica papaya which concentrated large Fe reserves exclusively in plastids called amyloplasts. Generally, Fe stored in amyloplast is considered bioavailable. Taken together, this study suggests dicot seeds store Fe mainly in the embryo, with a VIT1-dependent enrichment in its endodermal cell layer and indicate Carica papaya possess a strong Fe transporter at the plastid membrane. Once it is identified that might be useful in biofortification, as a novel tool to shift Fe to compartments where it is more bioavailable.

plant biology↗

bioRxiv2018

βVPE is involved in tapetal degradation and pollen development by activating proprotease maturation in Arabidopsis thaliana

Vacuolar processing enzyme (VPE) is responsible for the maturation and activation of vacuolar proteins in plants. We found that {beta}VPE was involved in tapetal degradation and pollen development by transforming proproteases into mature protease in Arabidopsis thaliana. {beta}VPE was expressed specifically in the tapetum from stages 5-8 of anther development. The {beta}VPE protein first appeared as a proenzyme and transformed into the mature enzyme before stages 7-8. The recombinant {beta}VPE protein self-cleaved and transformed to a 27-kD mature protein at pH 5.2. The mature {beta}VPE protein could induce the maturation of CEP1 in vitro. {beta}vpe mutants exhibited delayed vacuolar degradation and decreased pollen fertility. The maturation of CEP1, RD19A, and RD19C were seriously inhibited in {beta}vpe mutants. Our results indicate that {beta}VPE is a crucial processing enzyme that directly participates in the maturation of cysteine proteases before vacuolar degradation, and is indirectly involved in pollen development and tapetal cell degradation.\n\nHighlight{beta}VPE is a crucial processing enzyme that directly participates in the maturation of cysteine proteases before vacuolar degradation, and is indirectly involved in pollen development and tapetal cell degradation.

plant biology↗