Conclusion
In this study we performed GC-TOF-MS metabolite profiling of a tomato
RIL population and their parental lines grown in high phosphate and low
nitrate environments. Our results show clear genetic variation at the
metabolite level between the two parental lines, where the maternal
nutritional environment was also introducing variation within each
genotype. Elucidation of genetic and molecular aspects of metabolic
changes of seeds as a response to different maternal environments was
carried out by using metabolite correlation networks, followed by mQTL
analysis. In general the HP environment induced more metabolic changes
as compared to the LN environment. Correlation of metabolites within the
whole RIL population revealed a crosstalk between N and C metabolism in
which significant correlations were observed between amino acids and TCA
cycle intermediates. Besides mQTLs detected in the individual
environments and the genetic effects, many mQTLs were detected for G×E.
In spite of the strong correlations found between metabolites and
phenotypic traits, the detected mQTLs were hardly co-located with the
ones affecting phenotypic traits. This might be caused by the fact that
not a single metabolite, but a group of metabolites together influence
the phenotype. This study has provided novel insights towards better
understanding of the effect of maternal environment on tomato seed and
seedling performance by combining various physiological, omics and
genetical analyses. In addition to the new insights that have been
provided in this study, more in-depth investigations are needed to
further elucidate the regulation of the dry seed metabolome under
different nutritional environments and its influence on seed and
seedling performance.