Genetic determinants of seed protein plasticity in response to the environment in Medicago truncatula

Abstract

SUMMARY As the frequency of extreme environmental events is expected to increase with climate change, identifying candidate genes for stabilizing the protein composition of legume seeds or optimizing this in a given environment is increasingly important. To elucidate the genetic determinants of seed protein plasticity, major seed proteins from 200 ecotypes of Medicago truncatula grown in four contrasting environments were quantified after one‐dimensional electrophoresis. The plasticity index of these proteins was recorded for each genotype as the slope of Finlay and Wilkinson's regression and then used for genome‐wide association studies (GWASs), enabling the identification of candidate genes for determining this plasticity. This list was enriched in genes related to transcription, DNA repair and signal transduction, with many of them being stress responsive. Other over‐represented genes were related to sulfur and aspartate family pathways leading to the synthesis of the nutritionally essential amino acids methionine and lysine. By placing these genes in metabolic pathways, and using a M. truncatula mutant impaired in regenerating methionine from S‐methylmethionine, we discovered that methionine recycling pathways are major contributors to globulin composition establishment and plasticity. These data provide a unique resource of genes that can be targeted to mitigate negative impacts of environmental stresses on seed protein composition.

Identification of significant genome-wide associations and QTL underlying variation in seed protein composition in pea (Pisum sativumL.)

“…Understanding the types and proportions of different protein classes in pea seeds is crucial for improving the nutritional value and functional properties of their proteins. For protein composition analysis, SDS-PAGE-based densitometric quantification is considered a high-throughput and costeffective method and is widely used for large-scale germplasm screening of legumes [8,19,20,26,27] .…”

Recent progress in molecular genetics and omics-driven research in seed biology

“…In addition to genetic determinism and tissue distribution, the content and nature of storage compounds (including oil and proteins) and SMs are also shaped by the environment, and strongly impact the nutritional, agronomic or industrial quality of seeds (Figure 4). Many biotic and abiotic factors, such as drought or elevated temperatures can affect seed oil and protein composition [152][153][154][155][156], seed germination, and impact seedling vigour [157,158].…”