Chinese Bulletin of Botany ›› 2021, Vol. 56 ›› Issue (3): 275-283.

### QTL Mapping and Candidate Gene Analysis on Rice Leaf Water Potential

Chenyang Pan, Yue Zhang, Han Lin, Qianyu Chen, Kairu Yang, Jiaji Jiang, Mengjia Li, Tao Lu, Kexin Wang, Mei Lu, Sheng Wang, Hanfei Ye, Yuchun Rao*(), Haitao Hu*()

1. College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua 321004, China
• Received:2021-02-22 Accepted:2021-03-26 Online:2021-05-01 Published:2021-04-30
• Contact: Yuchun Rao,Haitao Hu

Abstract:

To reveal the role and genetic mechanism of genes related to leaf water potential (LWP) in rice drought resistance, the 120 recombinant inbred lines (RILs) populations derived from the cross of Nekken2 and HZ as well as the two parents were chosen as the experiment materials in this study. After testing and analyzing the leaf water potential at tillering stage, quantitative trait loci (QTL) were detected based on the molecular linkage map of these populations constructed by using high-throughput sequencing in the early stage. The experimental results showed that 5 QTLs related to leaf water potential at tillering stage were located on chromosome 2, 3, 4, 11 and 12, respectively, with LOD (likelihood of odd) value all above 2.5, one of which located on chromosome 4 with physical distance between 24 066 261 and 30 847 136 bp showed the highest LOD value of 5.15. Through quantitative analysis of these candidate genes relevant to leaf water potential within the QTL regions, 7 genes, LOC_Os02g56630, LOC_Os02g57720, LOC_Os02g57580, LOC_ Os04g43730, LOC_Os04g46490, LOC_Os04g44570, LOC_Os04g44060, were identified to have different expression levels between the two parents. LOC_Os04g46490, which located within the QTL region on chromosome 4, showed significant difference in gene expression and 6 differences at DNA sequences and changes at amino acids between two parents. By QTL mining and quantitative analysis of related genes, we discovered that these genes were associated with the regulation of leaf water potential, which may indirectly affect the drought resistance of rice. The detected QTL loci have important reference value for QTL fine mapping and genes cloning associated with drought tolerance, thus facilitating our understanding of the genetic basis of rice leaf water potential, and providing genetic resources for developing new drought-tolerant rice cultivars.