Maize

Functional characterization of candidate genes significantly associated with carbon isotope discrimination in maize

Sonja Blankenagel, Viktoriya Avramova, Eva Bauer, Chris-Carolin Schön
Project duration: 01.07.2015 - 30.06.2019
Project partner: Sonderforschungsbereich SFB924 "Molecular mechanisms regulating yield and yield stability in plants" (http://www.sfb924.wzw.tum.de)
Funding: Deutsche Forschungsgemeinschaft (DFG)

Project description:

Drought is one of the major constraints of plant productivity worldwide and therefore constitutes a highly important agronomic trait. We used a maize introgression library (IL) to identify genomic regions with impact on drought and/or growth related traits. A key region on chromosome 7 (chr7) was found through genetic mapping, which strongly influenced carbon isotope discrimination (delta¹³C), a trait which is a good predictor for drought tolerance in C3 plants due to its correlation with transpiration efficiency. In this chromosomal segment, we have identified candidate genes which are putatively associated with stomatal conductance and we hypothesize that they have an effect on delta¹³C and drought response. In the next project phase, we will characterize these genes with respect to their functional and molecular properties in maize and heterologous systems. We will investigate their native allelic variation in a maize diversity panel and assess their phenotypic effects in segregating maize populations. Using introgression lines with recombined donor fragments and two-segment combinations, we will be able to narrow down target regions and test effects of candidate genes in a homogenous, near-isogenic genetic background. Building on a transcriptome and whole genome sequence resource from the previous project phase we will characterize networks of genes which are differentially regulated under drought stress. A better understanding of the genetic basis and genes involved in delta¹³C and their possible effects on drought tolerance will aid in the genome-based improvement of C4 crop species such as maize. Our results may also contribute to extend the knowledge on C4 photosynthesis in maize and other C4 plants.