A missense mutation in the VHYNP motif of a DELLA protein causes a semi-dwarf mutant phenotype in Brassica napus
A missense mutation in the VHYNP motif of a DELLA protein causes a semi-dwarf mutant phenotype in Brassica napus
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DOI：
10.1007/s00122-010-1306-9
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发表时间：
2010-07-01
影响因子：
5.4
通讯作者：
Liu, Kede
中科院分区：
文献类型：
--
作者：
Liu, Chao;Wang, Jilin;Liu, Kede
虽然矮秆基因已被广泛应用于谷类作物的抗倒伏和提高收获指数，但倒伏仍然是油菜生产中的一个严重问题。通过对甘蓝型油菜小孢子培养株系的EMS诱变，获得了一个半矮秆甘蓝型油菜突变体DS-1。与野生型品种相比，该突变体的株高显著降低，这是因为该突变体的一次分枝位置较低，节间较短。这种矮秆是作为一个半显性基因DS-1遗传的。将DS-1基因定位在A6染色体上，并与来自BnRGA基因的微卫星标记BnEMS1125共分离。BnRGA编码一种Della蛋白，其功能是GA信号抑制因子。来自DS-1的BnRGA突变等位基因Bnrga-DS的表达导致了拟南芥的矮化表型。对DS-1和野生型品种的RGA开放阅读框(ORF)进行了比较测序，发现了一个从P到亮氨酸(L)的单一替换，可能导致GA信号的功能增益突变。带有这种定点突变的拟南芥同源基因Atrga-DS的表达也使拟南芥表现出矮化表型，这表明Bnrga-DS的VHYNP基序中的P-to-L突变是导致矮化的原因。酵母双杂交实验证实，在GA(3)存在的情况下，该突变抑制了Bnrga-DS/Atrga-DS与GA受体AtGID1A之间的相互作用，这表明Della蛋白VHYNP基序中保守的Pro残基直接参与了Della-GID1的相互作用。矮秆基因DS-1的鉴定和鉴定为其在甘蓝型油菜抗倒伏育种中的应用奠定了基础。
Although dwarf genes have been widely used to improve lodging resistance and enhance harvest index in cereal crops, lodging is still a serious problem in rapeseed (Brassica napus) production. A semi-dwarf B. napus mutant, ds-1, was identified through EMS mutagenesis of a microspore-cultured DH line. The mutant had a significant reduction in height due to a lower first branch position and shorter internodes when compared with wild-type cultivars. This dwarfism was inherited as a single semi-dominant gene, ds-1. DS-1 locus was mapped to chromosome A6, and co-segregated with a microsatellite marker BnEMS1125 derived from the gene BnRGA. BnRGA encodes a DELLA protein that functions as a GA signaling repressor. The expression of a mutant BnRGA allele from ds-1, Bnrga-ds, caused dwarf phenotypes in Arabidopsis. Comparative sequencing of RGA open-reading frames (ORFs) of ds-1 and wild-type cultivars revealed a single proline (P)-to-leucine (L) substitution that may lead to a gain-of-function mutation in GA signaling. The expression of the Arabidopsis homolog, Atrga-ds, bearing this site-directed mutation also rendered dwarf phenotypes in Arabidopsis, which demonstrated that the P-to-L mutation in the VHYNP motif of Bnrga-ds is responsible for the dwarfism. A yeast two-hybrid assay confirmed that this mutation inhibited the interaction between Bnrga-ds/Atrga-ds and the GA receptor, AtGID1A, in the presence of GA(3), suggesting that the conserved proline residue in the VHYNP motif of DELLA protein directly participates in DELLA-GID1 interaction. Identification and characterization of the dwarf gene ds-1 will facilitate its utilization in improving lodging resistance in Brassica breeding.