Abstract：
Plant height (PH) is an important factor affecting bast fiber yield in jute. Here, we report the mechanism of dwarfism in the \'Guangbaai\' (gba) of jute. The mutant gba had shorter internode length and cell length compared to the standard cultivar \'TaiZi 4\' (TZ4). Exogenous GA3 treatment indicated that gba is a GA-insensitive dwarf mutant. Quantitative trait locus (QTL) analysis of three PH-related traits via a high-density genetic linkage map according to re-seq showed that a total of 25 QTLs were identified, including 13 QTLs for PH, with phenotypic variation explained ranging from 2.42 to 74.16%. Notably, the functional mechanism of the candidate gene CoGID1a, the gibberellic acid receptor, of the major locus qPHIL5 was evaluated by transgenic analysis and virus-induced gene silencing. A dwarf phenotype-related single nucleotide mutation in CoGID1a was identified in gba, which was also unique to the dwarf phenotype of gba among 57 cultivars. Cogid1a was unable to interact with the growth-repressor DELLA even in the presence of highly accumulated gibberellins in gba. Differentially expressed genes between transcriptomes of gba and TZ4 after GA3 treatment indicated up-regulation of genes involved in gibberellin and cellulose synthesis in gba. Interestingly, it was found that up-regulation of CoMYB46, a key transcription factor in the secondary cell wall, by the highly accumulated gibberellins in gba promoted the expression of cellulose synthase genes CoCesA4 and CoCesA7. These findings provide valuable insights into fiber development affected by endogenous gibberellin accumulation in plants.
摘要：
株高(PH)是影响黄麻韧皮纤维产量的重要因素。这里,我们报道了黄麻的“广百”（gba）侏儒症的机制。与标准品种“太子4”（TZ4）相比，突变体gba的节间长度和细胞长度更短。外源GA3处理表明gba是对GA不敏感的矮突变体。根据re-seq通过高密度遗传连锁图谱对三个PH相关性状进行数量性状基因座（QTL）分析，结果表明共鉴定出25个QTL，包括13个PH的QTL，表型变异的解释范围为2.42％至74.16％。值得注意的是,候选基因CoGID1a的功能机制，赤霉素受体，通过转基因分析和病毒诱导的基因沉默评估主要基因座qPHIL5。在gba中鉴定出CoGID1a中与矮小表型相关的单核苷酸突变，在57个品种中，gba的矮化表型也是独一无二的。即使在gba中存在高度积累的赤霉素，Cogid1a也无法与生长抑制物DELLA相互作用。GA3处理后gba和TZ4转录组之间的差异表达基因表明gba中参与赤霉素和纤维素合成的基因上调。有趣的是,结果发现，次级细胞壁中的关键转录因子CoMYB46的上调，由gba中高度积累的赤霉素促进了纤维素合酶基因CoCesA4和CoCesA7的表达。这些发现为植物中内源性赤霉素积累影响的纤维发育提供了有价值的见解。
