Identification of QTL Associated with Hydrotropism in Maize Primary Root
Abstract
Hydrotropism enables plant roots to grow towards more moist area when the root experiences a moisture gradient in its surroundings. Thus, hydrotropism can increase the accessibility of roots to water, avoiding drought stress. Despite its important role in water acquisition, hydrotropism is not extensively studied, the genetic and molecular regulation of hydrotropism remains elusive. To identify the key molecular components involved in hydrotropism, a maize NAM (nested association mapping) population with 200 RILs (recombinant inbreed lines) was tested to examine various traits in hydrotropic processes. By combining the SNP (single nucleotide polymorphism) markers data available in the maize genome database with the traits studied, we conducted a QTL analysis using R and WinQTLCart software. We identified four QTL with a LOD score of 3 or greater, accounting for a total 38.4% of the hydrotropic variability. One QTL is located on chromosome 1, one QTL on chromosome 5, and two QTL on chromosome 7. The results suggest that hydrotropism in the primary root of maize may be controlled by a gene network system and the variability of hydrotropic response is primarily affected by four loci with relatively large effects instead of cumulative small effects of numerous loci. Future work includes validating the identified QTL, examining the interaction between these QTLs, and identifying candidate genes within the QTL regions.
Identification of QTL Associated with Hydrotropism in Maize Primary Root
Volstorff A
Hydrotropism enables plant roots to grow towards more moist area when the root experiences a moisture gradient in its surroundings. Thus, hydrotropism can increase the accessibility of roots to water, avoiding drought stress. Despite its important role in water acquisition, hydrotropism is not extensively studied, the genetic and molecular regulation of hydrotropism remains elusive. To identify the key molecular components involved in hydrotropism, a maize NAM (nested association mapping) population with 200 RILs (recombinant inbreed lines) was tested to examine various traits in hydrotropic processes. By combining the SNP (single nucleotide polymorphism) markers data available in the maize genome database with the traits studied, we conducted a QTL analysis using R and WinQTLCart software. We identified four QTL with a LOD score of 3 or greater, accounting for a total 38.4% of the hydrotropic variability. One QTL is located on chromosome 1, one QTL on chromosome 5, and two QTL on chromosome 7. The results suggest that hydrotropism in the primary root of maize may be controlled by a gene network system and the variability of hydrotropic response is primarily affected by four loci with relatively large effects instead of cumulative small effects of numerous loci. Future work includes validating the identified QTL, examining the interaction between these QTLs, and identifying candidate genes within the QTL regions.