青稞LTP蛋白基因blt14.2的克隆及其在低温下的表达

Isolation of a blt14.2 gene encoding LTP protein of hulless barley and its expression in low temperature

为了解LTP蛋白基因blt14.2在青稞中的功能,以青稞品种"昆仑12号"为实验材料,克隆得到编码该基因的cDNA序列全长470bp,其中包括249bp的开放阅读框,编码82个氨基酸残基,相对分子质量7 709.8,理论pI6.52,不稳定系数27.36,是一个稳定的蛋白质。LTP蛋白有2个跨膜区,1～19位置的是从膜内到膜外,57～76位置的是从膜外到膜内,总平均亲水性0.522,是一个高度亲水的小分子蛋白质。序列比对显示编码该蛋白的基因与大麦blt14.2基因具有较高的同源性(98.9%)。通过Real-time PCR检测得到blt14.2基因在4℃下处理48、24和12h的表达量分别是0h的14.6、13.6和8.3倍,SPSS分析显示blt14.2基因在不同低温胁迫时间下表达差异显著,说明该基因对青稞的耐寒性起到一定的作用。

Lipid transfer proteins（LTPs） have the ability to transfer phospholipids between donor and acceptor on the membrane of advanced plants. LTPs are important in the membrane forming in cells and related to the resistance to the extremely environment. In order to investigate the function of LTP（b/t14.2）in the hulless barley, the cDNA encoding bit14.2 was cloned from ＂KunLun12＂ by RT-PCR. The full length of cDNA ks 470 bp encoding a protein with 82 amino acids. It was a stable protein with the molecular weight of 7 709.8, theoretical pl 6.52, and coefficient of instability27.36. LTPs have two transmembrane domains,within the position of 1-19 aa （from inside to outside） and 57-76 aa （from outside to inside）. The protein is a small and highly hydrophilic protein with the average hydrophilicity of O. 522. The sequence is very similar to the gene from barley （Hordeum vulgare L. ） with the homology of 98.9%. Result from the Real-time PCR showed that the expression level of bit14.2 were increased to 8.3,13.6 and 14.6 times comapred with control respectively,after the plant under 4℃, for 12,24 and 48 h. The results proved the expression of bit14. 2 gene changed remarkably under different time of cold stress,and played a role on cold tolerance of hulless barley.