Genomic loci associated with leaf abscission contribute to machine picking and environmental adaptability in upland cotton ( Gossypium hirsutum L）

作者：棉花生物育种与综合利用全国重点实验室 日期：2023-10-23 访问量：

Hongge Li, Xiangru Wang, Ning Qin, Daowu Hu, Yinhua Jia, Gaofei Sun, Liangrong He, Hengheng Zhang, Panhong Dai, Zhen Peng, Nianchang Pang, Zhaoe Pan, Xiaomeng Zhang, Qiang Dong, Baojun Chen, Huiping Gui, Baoyin Pang, Xiling Zhang, Shoupu He, Meizhen Song, Xiongming Du

Journal of Advanced Research

Doi:10.1016/j.jare.2023.05.007

Abstract：

Introduction: Defoliation by applying defoliants before machine picking is an important agricultural practice that enhances harvesting efficiency and leads to increased raw cotton purity. However, the fundamental characteristics of leaf abscission and the underlying genetic basis in cotton are not clearlyunderstood.Objectives: In this study, we aimed to (1) reveal the phenotypic variations in cotton leaf abscission, (2)discover the whole-genome differentiation sweeps and genetic loci related to defoliation, (3) identifyand verify the functions of key candidate genes associated with defoliation, and (4) explore therelationship between haplotype frequency of loci and environmental adaptability.Methods: Four defoliation-related traits of 383 re-sequenced Gossypium hirsutum accessions were investigated in four environments. The genome-wide association study (GWAS), linkage disequilibrium (LD)interval genotyping and functional identification were conducted. Finally, the haplotype variation relatedto environmental adaptability and defoliation traits was revealed.Results: Our findings revealed the fundamental phenotypic variations of defoliation traits in cotton. Weshowed that defoliant significantly increased the defoliation rate without incurring yield and fiber qualitypenalties. The strong correlations between defoliation traits and growth period traits were observed. Agenome-wide association study of defoliation traits identified 174 significant SNPs. Two loci (RDR7 onA02 and RDR13 on A13) that significantly associated with the relative defoliation rate were described,and key candidate genes GhLRR and GhCYCD3;1, encoding a leucine-rich repeat (LRR) family proteinand D3-type cell cyclin 1 protein respectively, were functional verified by expression pattern analysisand gene silencing. We found that combining of two favorable haplotypes (HapRDR7 and HapRDR13)improved sensitivity to defoliant. The favorable haplotype frequency generally increased in high latitudesin China, enabling adaptation to the local environment.Conclusion: Our findings lay an important foundation for the potentially broad application of leveragingkey genetic loci in breeding machine-pickable cotton.