【摘要】 根据已发表的几种藜科植物甜菜碱醛脱氢酶(BADH)基因的同源保守区设计了一对引物,采用RT-PCR方法从盐生植物盐爪爪(Kalidium foliatum)中扩增出BADH基因的1个开放阅读框架,其核苷酸序列长1503bp,推测的氨基酸序列全长为500个氨基酸残基。核苷酸序列与藜科几种盐生植物如滨藜、碱蓬、菠菜、山菠菜和甜菜等的同源性为81%,与甜土植物水稻的同源性为69%。氨基酸序列与以上两类植物(盐生植物和甜土植物)的同源性比对为80%和71%,说明BADH基因在藜科盐生植物中是一种较高保守的基因。BADH基因编码的多肽在高等植物中行使重要的功能。用不同浓度的NaCl胁迫处理盐爪爪植株,BADHmRNA的表达水平比对照植株高,说明盐爪爪BADH基因的表达受盐诱导,间接说明甜菜碱醛脱氢酶催化合成的甜菜碱作为渗透调节的小分子物质,它的积累与盐胁迫存在紧密关联,本研究为进一步从生理和分子水平阐明盐爪爪的耐盐机制提供一定的参考。更多还原

【Abstract】 According to the published sequences of BADH cDNA of several other plants of Chenopodiaceae,two primers have been designed to amplify the fragment of BADH cDNA from Kalidium foliatum through RT-PCR(reverse transcription polymerase chain reaction).A 1503 bp fragment containing entire betaine aldehyde dehydrogenase(BADH)coding region of 500 amino acids(aa)has been obtained.Nucleotide sequence of KfBADH was similar to the corresponding fragment of BADH cDNA of several other plants,such as Atriplex centralasiatica,Atriplex hortensis,Spinacia oleracea,Suaeda liaotungensis,Beta vulgaris subsp.vulgaris,Oryza sativa and so on.Encoded protein by KfBADH and BADH protein from above mentioned plants also shared 71% identity at the amino acid level.The result showed BADH gene was conserved,especially in Chenopodiaceae and encoded functional protein may play an important role in high plants during salt stress.Semi-quantitative gene expression analysis showed that the level of BADH mRNA in plants treated with different NaCl concentration is higher than that in the control plants,suggesting that the accumulation of betaine catalyzed by betaine aldehyde dehydrogenase as an effective osmolyte is important for Kalidium foliatum during salt stress.The study provided material for further exploring salt tolerant mechanisms of Kalidium foliatum in physiological and molecular aspects.更多还原