互花米草NAC48转录因子的克隆与功能鉴定

Cloning and Functional Identification of NAC48 Transcription Factor from Spartina alterniflora

互花米草是一种广泛分布于中国海岸盐沼地的入侵植物,其茎秆粗壮、根系发达、能够在高盐胁迫下生长、发育并完成生殖。由于其与主要禾本科农作物同源性高,研究其耐盐机制对促进农林作物耐盐改良与开发具有重要意义。本研究克隆了1个互花米草转录因子基因SaNAC48,对其氨基酸进行分析发现,SaNAC48与C4植物高粱、玉米以及甘蔗中的NAC48蛋白最为相近。借助烟草瞬时表达发现SaNAC48表达定位于细胞核,并通过酵母表达体系验证发现其具有转录激活活性,表明SaNAC48可发挥转录因子功能。将SaNAC48过表达至模式植物拟南芥中,其T2代植株显现矮小、叶片卷曲等表型。通过对过表达植株进行盐胁迫处理,发现过表达植株具有更强的耐盐性,进一步验证SaNAC48的功能。本研究揭示了SaNAC48作为重要的转录因子参与互花米草响应盐胁迫应答的调控机制,为后续该基因农作物耐盐改良提供理论基础。

Spartina alterniflora is a kind of important halophyte widely distributed in coastal salt marsh.Spartina alterniflora has thick stems and widespread roots as a result it can grow well and complete the whole reproduction period under high salt stress.Studying the salt tolerance mechanism of S.alterniflora has great significance on promoting the improvement and development of agricultural and forestry salt-tolerant crops.In this study,we cloned a S.alterniflora transcription factor-coding gene SaNAC48.By analyzing the amino acid of SaNAC48,we found it was most closed with C4 plant like Sorghum bicolor,Zea mays,Oryza sativa.Tobacco transient expression experiments demonstrated SaNAC48 localized in the nucleus and yeast one-hybrid assays showed SaNAC48 has strong transcriptional activation activity suggested tha t SaNAC48 might play a regulatory role of transcription factor.We then overexpressed SaNAC48 in Arabidopsis thaliana,and T2 transgenic lines showed development phenotypes such as short stem and curl leaves.The function of SaNAC48 on salt tolerance was further verified by salt treatment experiment and we found SaNAC48 overexpressed plants had stronger salt tolerance.The results of this study revealed that SaNAC48 might participate in response to salt stress by functioning as an important transcription factor and provides a theoretical basis for genes remolding and salt tolerance improvement of crops.