Fine mapping of the fiber length-related qFL-A12-2 QTL through the use of chromosome segment substitution lines and candidate gene validation

• Published in: Industrial crops and products Vol. 220; p. 119093
• Main Authors: Xiao, Xianghui, Liu, Ruixian, Wang, Yongbo, Gong, Juwu, Li, Pengtao, Gong, Wankui, Yang, Rui, Liu, Aiying, Ge, Qun, Zhang, Haibo, Chen, Yu, Sun, Zhihao, Liu, Yangming, Peng, Renhai, Shang, Haihong, Li, Junwen, Yan, Haoliang, Pan, Jingtao, Shi, Yuzhen, Yuan, Youlu, Lu, Quanwei
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-11-2024
• Subjects: BSA; Fiber length; Fine mapping; GhALMT12_A12; Single segment introgression line; Fine mapping; BSA; Fiber length; GhALMT12_A12; Single segment introgression line
• ISSN: 0926-6690
• DOI: 10.1016/j.indcrop.2024.119093

Fiber length (FL) is one of the primary factors used to determine the quality of cotton fibers, serving as a primary target for the domestication and breeding of cotton plants through artificial selection. While many studies have identified quantitative trait loci (QTLs) associated with fiber length, few efforts have explored the mechanisms underlying the development of cotton fibers through fine mapping or the validation of related candidate genes. In a previous study, qFL-A12–2 was identified as a QTL on chromosome A12 that was associated with higher levels of fiber quality in the MBI7747 (BC4F3:5) chromosome segment substitution line (CSSL). For fine mapping the QTL, a single-segment substitution line (CSSL-023) screened from BC5F2 was backcrossed with the recurrent parental CCRI45 line to establish a large segregation population. Subsequently, 2092 individual BC6F2 specimens were utilized in a fine-mapping effort employing highly dense simple sequence markers, which narrowed qFL-A12–2 to a 0.65 Mb genomic region in Gossypium hirsutum containing 12 annotated genes. The most promising candidate gene within this interval was identified through qRT-PCR and complete coding sequence comparative analyses as GhALMT12_A12, which encodes an aluminum-activated malate transporter. Two non-synonymous mutations were identified when the protein-coding portions of GhALMT12_A12 were compared among the Hai1, MBI7747, and CCRI45 varieties. Verification of GhALMT12_A12 silencing by VIGS in cotton revealed that the FL of silenced plants was significantly shorter than that of the control plants. When overexpressed, GhALMT12_A12 significantly enhanced Arabidopsis resistance to salt stress and drought conditions through altering ion transport. The outcomes underscore the notable function of GhALMT12_A12 in developing cotton fibers, providing a fundamental basis for scholars aiming at augmenting the length of cotton fibers.
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•Fine mapping of the qFL-A12–2 interval was conducted, and finally the GhALMT12_A12 candidate gene was identified.•Revealed that the GhALMT12_ A12 gene was derived from the G. barbadense Hai1.•GhALMT12_A12 positively regulates the elongation of cotton fibers.