Biology subjects

VanGessel, C.

Publications and source records attributed to VanGessel, C..

3 recordsLinked to original sources

bioRxiv2023

Globally-deployed sorghum aphid resistance gene RMES1 is vulnerable to biotype shifts but being bolstered by RMES2

Durable host plant resistance (HPR) to insect pests is critical for sustainable agriculture. Natural variation exists for aphid HPR in sorghum (Sorghum bicolor) but the genetic architecture and phenotype has not been clarified for most sources. To assess the threat of a sorghum aphid (Melanaphis sorghi) biotype shift, we characterized the phenotype of Resistance to Melanaphis sorghi 1 (RMES1) and contributing HPR architecture in globally-admixed populations selected under severe aphid infestation in Haiti. We found RMES1 reduces sorghum aphid fecundity but not bird cherry-oat aphid (Rhopalosiphum padi) fecundity, suggesting a discriminant HPR response typical of gene-for-gene interaction. A second resistant gene, RMES2, were more frequent than RMES1 resistant alleles in landraces and historic breeding lines. RMES2 contributes early and mid-season aphid resistance in a segregating F2 population, however RMES1 was only significant with mid-season fitness. In a fixed population with high aphid resistance, RMES1 and RMES2 were selected for demonstrating a lack of significant antagonistic pleiotropy. Associations with resistance co-located with cyanogenic glucoside biosynthesis genes support additional HPR sources. Globally, therefore, a vulnerable HPR source (RMES1) is bolstered by a second common source of resistance in breeding programs (RMES2) which may be staving off a biotype shift. HIGHLIGHTThe globally-deployed sorghum aphid resistance gene, RMES1, reduces aphid reproduction and therefore is vulnerable to a biotype shift. A second major gene, RMES2, and cyanogenesis may increase global durability of resistance.

plant biology↗

bioRxiv2022

Transcriptional signatures of wheat inflorescence development

In order to maintain global food security, it will be necessary to increase yields of the cereal crops that provide most of the calories and protein for the worlds population, which includes common wheat (Triticum aestivum L.). An important factor contributing to wheat yield is the number of grain-holding spikelets which form on the spike during inflorescence development. Characterizing the gene regulatory networks controlling the timing and rate of inflorescence development will facilitate the selection of natural and induced gene variants that contribute to increased spikelet number and yield. In the current study, co-expression and gene regulatory networks were assembled from a temporal wheat spike transcriptome dataset, revealing the dynamic expression profiles associated with the progression from vegetative meristem to terminal spikelet formation. Consensus co-expression networks revealed enrichment of several transcription factor families at specific developmental stages including the sequential activation of different classes of MIKC-MADS box genes. This gene regulatory network highlighted interactions among a small number of regulatory hub genes active during terminal spikelet formation. Finally, the CLAVATA and WUSCHEL gene families were investigated, revealing potential roles for TaCLE13, TaWOX2, and TaWOX7 in wheat meristem development. The hypotheses generated from these datasets and networks further our understanding of wheat inflorescence development.

plant biology↗

bioRxiv2020

Effect of phyB and phyC loss-of-function mutations on the wheat transcriptome under short and long day photoperiods

BackgroundPhotoperiod signals provide important cues by which plants regulate their growth and development in response to predictable seasonal changes. Phytochromes, a family of red and far-red light receptors, play critical roles in regulating flowering time in response to changing photoperiods. A previous study showed that loss-of-function mutations in either PHYB or PHYC result in large delays in heading time and in the differential regulation of a large number of genes in wheat plants grown in an inductive long day (LD) photoperiod. ResultsWe found that under non-inductive short-day (SD) photoperiods, phyB-null and phyC-null mutants were taller, had a reduced number of tillers, longer and wider leaves, and headed later than wild-type plants. Unexpectedly, both mutants flowered earlier in SD than LD, the inverse response to that of wild-type plants. We observed a larger number of differentially expressed genes between mutants and wild-type under SD than under LD, and in both cases, the number was larger for phyB than for phyC. We identified subsets of differentially expressed and alternatively spliced genes that were specifically regulated by PHYB and PHYC in either SD or LD photoperiods, and a smaller set of genes that were regulated in both photoperiods. We observed significantly higher transcript levels of the flowering promoting genes VRN-A1, PPD-B1 and GIGANTEA in the phy-null mutants in SD than in LD, which suggests that they could contribute to the earlier flowering of the phy-null mutants in SD than in LD. ConclusionsOur study revealed an unexpected reversion of the wheat LD plants into SD plants in the phyB-null and phyC-null mutants and identified candidate genes potentially involved in this phenomenon. Our RNA-seq data provides insight into light signaling pathways in inductive and non-inductive photoperiods and a set of candidate genes to dissect the underlying developmental regulatory networks in wheat.

plant biology↗