Biology subjects

Moreno Beltran, J. C.

Publications and source records attributed to Moreno Beltran, J. C..

5 recordsLinked to original sources

bioRxiv2024

DWARF14 and KARRIKIN INSENSITIVE2 mediate signaling of the apocarotenoid zaxinone in Arabidopsis

The natural growth regulator zaxinone increases the levels of the phytohormones strigolactone (SL) and abscisic acid in Arabidopsis (Arabidopsis thaliana) via unknown mechanisms. We demonstrate that parts of the effects of zaxinone in Arabidopsis depend on the SL receptor DWARF14 (AtD14), the karrikin receptor KARRIKIN INSENSITIVE2 (AtKAI2), and the F-Box protein MORE AXILLARY BRANCHING2 (AtMAX2) that mediates the signaling of SLs and karrikins. Binding assays and co-crystallization revealed zaxinone as an additional ligand of AtD14 and an SL antagonist that interrupts the interaction of AtD14 with AtMAX2. Zaxinone also bound to AtKAI2. These findings unveil a perception mechanism for zaxinone in Arabidopsis and demonstrate the capability of AtD14 and AtKAI2 to bind signaling molecules, other than strigolactones or karrikins, and mediate their transduction.

plant biology↗

bioRxiv2023

β-ionone regulates Arabidopsis thaliana transcriptome and increases its resistance against Botrytis cinerea

Carotenoids are isoprenoid pigments vital for photosynthesis. Moreover, they are the precursor of apocarotenoids that include the phytohormones abscisic acid (ABA) and strigolactones (SLs), and retrograde signaling molecules and growth regulators, such as {beta}-cyclocitral and zaxinone. The apocarotenoid {beta}-ionone ({beta}-I) was previously reported to exert antimicrobial effects. Here, we showed that the application of this scent to Arabidopsis plants at micromolar concentrations caused a global reprogramming of gene expression, affecting thousands of transcripts involved in stress tolerance, growth, hormone metabolism, pathogen defense and photosynthesis. These changes, along with modulating the levels of the phytohormones ABA, jasmonic acid and salicylic acid, led to enhanced Arabidopsis resistance to Botrytis cinerea (B.c.), one of the most aggressive and widespread pathogenic fungi affecting numerous plant hosts and causing severe losses of postharvest fruits. Pre-treatment of tobacco and tomato plants with {beta}-I followed by inoculation with B.c. confirms the conserved effect of {beta}-I and induced immune responses in leaves and fruits. Moreover, there was reduced susceptibility to B.c. in LYCOPENE {beta}-CYCLASE- expressing tomato fruits possessing elevated levels of the endogenous {beta}-I, indicating beneficial biological activities of this compound in planta. Our work unraveled {beta}-I as a further carotenoid-derived regulatory metabolite and opens up new possibilities to control B.c. infection by establishing this natural volatile as an environmentally friendly bio-fungicide.

plant biology↗

bioRxiv2022

The Arabidopsis D27like1 is a novel Isomerase that Contributes to SL Biosynthesis and Negatively Impacts ABA Level

The enzyme DWARF27 (D27) catalyzes the reversible isomerization of all-trans- into 9-cis-{beta}-carotene, initiating strigolactone (SL) biosynthesis. Genomes of higher plants encode two D27-homologs, D27-like1 and -like2, with unknown functions. Here, we investigated the enzymatic activity and biological function of the Arabidopsis D27-like1. In vitro enzymatic assays and Expression in Synechocystis sp. PCC6803 revealed a yet not reported 13-cis/15-cis/9-cis- and a 9-cis/all-trans-{beta}-carotene isomerization. Although disruption of AtD27-like1 did not cause SL deficiency phenotypes, overexpression of AtD27-like1 in the Atd27 mutant restored the more-branching phenotype, indicating a contribution of AtD27-like1 to SL biosynthesis. Accordingly, generated Atd27 Atd27like1 double mutants showed more pronounced branching phenotype, compared to Atd27. The contribution of AtD27-like1 to SL biosynthesis is likely due to its formation of 9-cis-{beta}-carotene that was present at higher levels in AtD27-like1 overexpressing lines. In contrast, AtD27-like1 expression correlated negatively with the content of 9-cis-violaxanthin, a precursor of abscisic acid (ABA), in shoots. Consistently, ABA levels were higher in shoots and also in dry seeds of the Atd27like1 and Atd27 Atd27like1 mutants. Transgenic lines expressing {beta}-glucuronidase (GUS) driven by the AtD27LIKE1 promoter and transcript analysis performed with hormone-treated Arabidopsis seedlings unraveled that AtD27LIKE1 is expressed in different tissues and regulated ABA and auxin. Taken together, our work revealed a cis/cis-{beta}-carotene isomerase activity that affects the content of both cis-carotenoid derived plant hormones ABA and SLs.

plant biology↗

bioRxiv2021

2',3'-cAMP treatment mimics abiotic stress response

The role of the RNA degradation product 2,3-cyclic adenosine monophosphate (2,3-cAMP) is poorly understood. Recent studies have identified 2,3-cAMP in plant material and determined its role in stress signaling. The level of 2,3-cAMP increases upon wounding, dark, and heat, and 2,3-cAMP by binding to an RNA-binding protein, Rbp47b, promotes stress granule (SG) assembly. To gain further mechanistic insight into 2,3-cAMP function, we used a multi-omics approach combining transcriptomics, metabolomics, and proteomics to dissect Arabidopsis response to 2,3-cAMP treatment. We demonstrated that 2,3-cAMP is metabolized into adenosine, suggesting that the well-known cyclic nucleotide-adenosine pathway from human cells might also exist in plants. Transcriptomic analysis revealed only minor overlap between 2,3-cAMP-and adenosine-treated plants, suggesting that these molecules act through independent mechanisms. Treatment with 2,3-cAMP changed the levels of hundreds of transcripts, proteins, and metabolites, many previously associated with plant stress responses including protein and RNA degradation products, glucosinolates, chaperones and SG components. Finally, we demonstrated that 2,3-cAMP treatment influences the movement of processing bodies, supporting the role of 2,3-cAMP in the formation and motility of membraneless organelles.

plant biology↗

bioRxiv2021

Manipulation of carotenoid metabolism stimulates biomass and stress tolerance in tomato

Improving yield, nutritional value and tolerance to abiotic stress are major targets of current breeding and biotechnological approaches that aim at increasing crop production and ensuring food security. Metabolic engineering of carotenoids, the precursor of Vitamin-A and plant hormones that regulate plant growth and response to adverse growth conditions, has been mainly focusing on provitamin A biofortification or the production of high-value carotenoids. Here, we show that the introduction of a single gene of the carotenoid biosynthetic pathway in different tomato cultivars simultaneously improved photosynthetic capacity and tolerance to various abiotic stresses (e.g., high light, salt, and drought), caused an up to 77% fruit yield increase and enhanced fruits provitamin A content and shelf life. Our findings pave the way for developing a new generation of crops that combine high productivity and increased nutritional value with the capability to cope with climate change-related environmental challenges.

plant biology↗