Molecular bases for drought tolerance in common vetch: designing new molecular breeding tools

Abstract

Background: Common vetch (Vicia sativa L.) is a forage grain legume of high protein content and high nitrogen fixation, relevant in sustainable agriculture systems. Drought is the main limiting factor of this crop yield. Genetic resources collections are essential to provide genetic variability for breeding. The analysis of drought associated parameters has allowed us to identify drought tolerant and sensitive ecotypes in a vetch core collection. Results: To understand the mechanisms involved in drought response we analysed transcriptomic differences between tolerant and sensitive accessions. Polymorphic variants (SNPs and SSRs) in these differential expressed genes (DEGs) have also been analysed for the design of drought-associated markers. A total of 1332 transcripts were commonly deregulated in both genotypes under drought. To know the drought adaptive response, we also analysed DEGs between accessions. A total of 2646 transcripts are DEG between sensitive and tolerant ecotypes, in watered and drought conditions, including important genes involved in redox homeostasis, cell wall modifications and stress-response. The integration of this functional and genetic information will contribute to understand the molecular mechanisms of drought response and the adaptive mechanisms of drought tolerance in common vetch. The identification of polymorphic variants in these DEGs has also been screened for the design of droughtassociated markers that could be used in future breeding program strategies. Conclusions: Our studies shed light for the first time in common vetch about the genes and pathways associated with drought tolerance. In addition, we identify over 100 potential drought associated polymorphism, as SNPs or SSRs, which are differently present in drought and tolerant genotypes. The use of these molecular markers for trait prediction would enable the development of genomic tools for future engineering strategies by screening of germplasm crop collections for traits related with crop drought resilience, adaptability or yield in vetch.

Common Vetch, Valuable Germplasm for Resilient Agriculture: Genetic Characterization and Spanish Core Collection Development

“…The parameter in which we have found the greatest variations was SC ( Figure 3A ). Recently, this parameter has been shown to be crucial to allow the identification of potential drought-tolerant and drought-sensitive common vetch varieties ( De la Rosa et al, 2020 ), supporting the use of this parameter to identify Vicia varieties potentially tolerant to water stress. Based on this characterization approach, we can identify interesting breeding candidates from this VCC, such as accessions 281, 528, 529, or 534 with good yield levels and optimal values of SC.…”

“…The availability in the genebank databases of V. sativa ESTs has allowed the identification of different polymorphic SSR alleles in coding sequences, although in most cases, the evaluation of polymorphisms and the experimental development and validation of these markers have not been carried out ( Chung et al, 2013 ; Liu et al, 2014 ; De la Rosa et al, 2020 ). To analyze their polymorphism and amplification specificity, primers were designed to amplify 24 of these loci.…”

“…Previously, it has been shown that the measurement of different parameters to identify drought-tolerant and drought-sensitive genotypes seems to depend on the species under study, as different species may possess different mechanisms of drought tolerance ( Silva et al, 2011 ). In the present work, we use the SC, RWC, and SPAD index that have been shown to correlate with drought tolerance in different species, including common vetch ( Colom and Vazzana, 2003 ; Li et al, 2006 ; Silva et al, 2011 ; De la Rosa et al, 2020 ). The SC is the parameter with the greatest variation.…”

“…SC was measured in the field when 50% of plants were flowering on a total of 10 plants per accession and in five leaves per plant on the first expanded leaf using a steady-state leaf porometer (SC-1, Decagon-Devices, LabFerrer, Spain). SC (mmol m –2 s –1 ) was done in duplicate and repeatedly during consecutive days as described ( De la Rosa et al, 2020 ). Mean values, standard deviation, and maximum and minimum values for these data were calculated using SPSS software.…”

An efficient root transformation system for recalcitrantVicia sativa

“…Current research focusses on understanding the molecular basis of important agricultural traits, aiming to facilitate molecular plant breeding (Moose and Mumm, 2008). The recent emergence of transcriptome data (Kim et al, 2015;Dong et al, 2017) will accelerate the identification of the genes controlling traits such as pod shattering (Dong et al, 2017), γ-glutamyl-β-cyanoalanine toxin accumulation (Kim et al, 2015) and drought tolerance in vetch (De la Rosa et al, 2020). However, it is difficult to demonstrate the function of candidate genes due to the lack of a robust transformation and plant regeneration system (Ford et al, 2008;Nguyen et al, 2020).…”