Effects of Parental Temperature and Nitrate on Seed Performance are Reflected by Partly Overlapping Genetic and Metabolic Pathways

Abstract

Seed performance is affected by the seed maturation environment, and previously we have shown that temperature, nitrate and light intensity were the most influential environmental factors affecting seed performance. Seeds developed in these environments were selected to assess the underlying metabolic pathways, using a combination of transcriptomics and metabolomics. These analyses revealed that the effects of the parental temperature and nitrate environments were reflected by partly overlapping genetic and metabolic networks, as indicated by similar changes in the expression levels of metabolites and transcripts. Nitrogen metabolism-related metabolites (asparagine, γ-aminobutyric acid and allantoin) were significantly decreased in both low temperature (15 °C) and low nitrate (N0) maturation environments. Correspondingly, nitrogen metabolism genes (ALLANTOINASE, NITRATE REDUCTASE 1, NITRITE REDUCTASE 1 and NITRILASE 4) were differentially regulated in the low temperature and nitrate maturation environments, as compared with control conditions. High light intensity during seed maturation increased galactinol content, and displayed a high correlation with seed longevity. Low light had a genotype-specific effect on cell surface-encoding genes in the DELAY OF GERMINATION 6-near isogenic line (NILDOG6). Overall, the integration of phenotypes, metabolites and transcripts led to new insights into the regulation of seed performance.

Environmental and genetic effects on tomato seed metabolic balance and its association with germination vigor

“…This is in contrast to previous studies on the effect of salinity on tomato pericarp metabolites [73, 74] and of temperature and nitrogen on Arabidopsis seeds [75]. Nevertheless, it has been shown that different parts of the plant, even different parts of the fruit, can have different metabolic responses to salt stress [73].…”

“…Galactinol is related to the raffinose family of oligosaccharides and a precursor in raffinose biosynthesis from galactose (KEGG). It has been shown to increase in Arabidopsis seeds developed under high light intensity, and was correlated to seed longevity [75]. Transcripts of Galactinol synthase accumulate prior to desiccation in tomato and maize seeds [103, 104].…”

Seed Biology Updates – Highlights and New Discoveries in Seed Dormancy and Germination Research

“…Nitrate is a major signal in the soil environment for seeds to detect vegetation gaps and germinate in the desirable spots with the likelihood of successful seedling establishment (Bewley et al, 2013). Nitrate signals received by the maternal plants are integrated with temperature signals during seed development and affect performance of mature seeds (He et al, 2016). Seed responses to nitrate, in terms of dormancy release, are well known, however, the mechanisms of nitrate-responsive gene expression in seeds have been elusive.…”

Novel loci and a role for nitric oxide for seed dormancy and preharvest sprouting in barley

“…Environmental factors in the maternal environment, such as temperature, nitrogen availability, and light intensity, affect seed dormancy (He et al, ; Rodriguez, Margineda, Gonzalez‐Martin, Insausti, & Benech‐Arnold, ; Springthorpe & Penfield, ), and the Arabidopsis seed transcriptome is particularly temperature sensitive. In a pioneering study on Arabidopsis seed dormancy, a quantitative trait locus (QTL) was identified, termed Delay of Germination 1 ( DOG1 ; Alonso‐Blanco, Bentsink, Hanhart, Vries, & Koornneef, ), and homologous Triticeae DOG1‐like genes were identified, but not annotated, in barley and wheat (Ashikawa, Mori, Nakamura, & Abe, ).…”