摘要：

分蘖高于主茎是困扰高粱品种整齐度和机械化生产的重要原因之一,为了阐明高粱调控分蘖高度基因的作用机制,提高高粱品种整齐度、选育适宜机械化生产高粱品种,依据前期的定位结果,利用15份分蘖与主茎整齐一致和17份分蘖高于主茎的高粱品种组成自然群体对候选基因进行验证,发现SNP3位点影响分蘖高度,所属基因为Sobic.009G213300.1.v3.2,命名为SbTH,位于水解酶_4保守区域。以分蘖高度与主茎一致的K35-Y5和分蘖高于主茎的1383为材料,通过实时荧光定量PCR分析SbTH基因在高粱不同组织中的表达模式。结果表明,2个材料SbTH基因在根和叶中均有表达,虽然表达量有差异,但趋势基本一致;1383主茎和分蘖茎基因表达量和趋势也基本一致,而K35-Y5在主茎开花期时呈反向表达,主茎表达量达到最高,同期的分蘖茎表达量降到最低。分析认为,SbTH在K35-Y5分蘖中表达量低,控制了分蘖节间的过度生长,形成主茎与分蘖高度一致的株型,而在1383分蘖中表达量高,促进分蘖节间的生长,使得分蘖比主茎高,SbTH基因在主茎开花期的差异表达是影响分蘖株高的关键。

关键词: 高粱, 分蘖高度, 定量表达

Abstract:

Tiller higher than main stem is one of the important reasons that make the uniformity of sorghum varieties and mechanized production of sorghum complicated.In order to clarify the mechanism of the gene that regulates the tiller height in sorghum,improve the uniformity of sorghum varieties and breed sorghum varieties suitable for mechanized production,based on the mapping results of our previous studies,15 of the sorghum variety whose tiller height was consistent with main stem height as well as 17 of the sorghum variety whose tiller height was higher than main stem height,were selected to form the natural population to have the candidate genes tested.It was found that it was the SNP3 locus belonging to the gene Sobic.009G2133001.v3.2 located in the conserved domains of Hydrolase_4 affects the tiller height,it was named SbTH.With two sorghum varieties K35-Y5 and 1383 taken as material,the expression patterns of gene SbTH in different sorghum tissues were analyzed by Real-time fluorescence quantitative PCR.The results showed that the SbTH gene got expressed in both the roots and the leaves.Though the expression levels were different,the trends were basically the same.In the stem of variety 1383 whose tiller was higher than main stem,the expression level and trend were almost the same.Only in variety K35-Y5 whose tiller height was consistent with main stem height,at anthesis of main stem,reverse expression pattern was observed.While the expression level of main stem reached the maximum,the expression level of tiller was lowered to the minimum.From above results,we concluded that the expression level of SbTH was low in the tiller of K35-Y5,thus the overgrowth of the tiller internodes got controlled,forming the plant phenotype whose stem and tiller had the same height.The expression level of SbTH was high in the tiller of variety 1383,thus the growth of tiller internodes was promoted,which made the tiller be higher than the stem.Therefore,it is believed that the differential expression of gene SbTH at anthesis of main stem is the key to tiller height regulation.

Key words: Sorghum, Tiller height, Quantitative expression