过量表达SbWRKY50基因对高粱田间长势的影响

Effects of SbWRKY50 Overexpression on the Growth of Sorghum in Field

叶片衰老是一个由复杂调控网络调控的生物学过程,该调控网络包括环境因素和内部因子,如转录因子(Transcriptional factors,TFs)和植物激素,其中,乙烯(Ethylene ET)对于植物衰老尤为关键。高粱(Sorghum bi⁃color L.)WRKY家族转录因子SbWRKY50是乙烯信号途径中关键成员乙烯不敏感3(ETHYLENE INSENSITIVE 3 EIN3)的直接靶标,能够抑制高粱叶片衰老。然而,SbWRKY50在田间是否能够通过调控叶片衰老影响高粱农艺性状仍然未知。文章对SbWRKY50过表达高粱的田间表型进行分析,并对SbWRKY50过表达高粱和野生型进行黑暗处理,检测叶绿素含量、鲜质量、干质量、乙烯合成速率。结果表明,过表达植株在田间自然条件下依然可以延缓高粱衰老;衰老相关基因SbSAG20、SbSAG21与SbSAG39的表达分析发现,这些基因的表达量在SbWRKY50过表达高粱中显著低于野生型。表明SbWRKY50通过抑制衰老相关基因表达延缓高粱衰老。SbWRKY50过表达高粱相比于野生型更为滞绿,且叶绿素含量、鲜质量、干质量显著高于野生型,表明SbWRKY50过表达可以增加高粱的田间生物量。综上,SbWRKY50过表达不仅可以延缓高粱衰老,而且能够增加高粱生物量。

The onset of leaf senescence is governed by a complex regulatory network including environmental cues and internal factors such as transcription factors(TFs)and phytohormones,in which ethylene(ET)is one key inducer.The TF SbWRKY50 of WRKY family from Sorghum bicolor L.is a direct target of the key component ETHYLENE INSENSITIVE3(EIN3)in ET signalling,functioning for leaf senescence repression.However,it remains unknown whether SbWRKY50 can affect sorghum agronomic traits by regulating leaf senescence in the field.In this paper,field phenotypic analysis of SbWRKY50 overexpressing sorghum was conducted,and the chlorophyll content,fresh weight,dry weight,and ethylene synthesis rate of SbWRKY50 overexpressing sorghum and wild-type sorghum were detected after dark treatment.The results found that overexpressing plants could still delay sorghum senescence under natural field conditions.Expression analysis of senescencerelated genes SbSAG20,SbSAG21,and SbSAG39 revealed that the expression levels of these genes were significantly lower in SbWRKY50 overexpressing sorghum than that of wild-type.The results showed that SbWRKY50 delayed sorghum senescence by inhibiting the expression of senescence-related genes.Compared with wild-type,SbWRKY50 overexpressing sorghum was greener,and chlorophyll content,fresh weight,and dry weight were significantly higher than those of wild-type.In conclusion,SbWRKY50 overexpression could not only delay sorghum senescence but also increase sorghum biomass.