巴西橡胶树HbWRKY基因家族10个成员在染色体上的定位

Cytogenetic Localization of 10 HbWRKY Gene Family Members on the Chromosomes of Hevea brasiliensis

HbWRKY是橡胶树中的一类转录因子基因家族,该家族基因编码的蛋白质参与橡胶树的产胶、衰老和抗逆胁迫等生理生化过程,植物激素类物质刺激(如乙烯利、茉莉酸、水杨酸等)、病原菌侵染和机械伤害均能诱导HbWRKYs基因的表达。目前,该基因家族的大部分基因已被克隆和分析,但这些基因在染色体上的具体位置尚未确定。本研究以巴西橡胶树热研7-33-97品系为材料,利用荧光原位杂交技术(FISH)和原位PCR技术对HbWRKYs基因家族中10个成员(HbWRKY1、HbWRKY2、HbWRKY3、HbWRKY4、HbWRKY5、HbWRKY7、HbWRKY9、HbWRKY11、HbWRKY27和HbWRKY75)进行了物理定位分析。结果表明:HbWRKY1、HbWRKY4和HbWRKY5基因同时定位在第9号染色体上,其中HbWRKY1和HbWRKY4在第9号染色体短臂上,其信号位点距离着丝粒的平均百分距分别为57. 38和4. 57,HbWRKY5在第9号染色体长臂上,其信号位点距离着丝粒的平均百分距为31. 67; HbWRKY2、HbWRKY3、HbWRKY7、HbWRKY9、HbWRKY11和HbWRKY75基因分别定位在第8、3、4、10、2和7号染色体的短臂上,信号位点距离着丝粒的平均百分距分别为6. 00、12. 30、4. 40、45. 21、5. 74和26. 11; HbWRKY27基因定位在第6号染色体长臂上,其信号位点距离着丝粒的平均百分距为38. 88。本研究还讨论了这些基因与其他已定位基因之间的位置关系。

HbWRKY is one of transcription factor gene families in Hevea brasiliensis （Willd. ex A. Juss. ）Mall. Arg. , and these family members are involved in the physiological and biochemical processes such as gum produc- tion, senescence and stress resistance of Hevea brasiliensis （ Willd. ex A. Juss. ） Mall. Arg.. Treatments by any of phytohormones （such as ethephon,jasmonic acid and salicin acid, etc. ） ,pathogen infestation or mechanical damage could result in the changes on transcriptional levels of HbWRKYs. At present, most members of this gene family have been cloned and analyzed, but the physical location of these genes on the chromosome has not yet been determined. In this work, by employment of FISH and in situ PCR techniques, we determined the physical positions of ten Hb- WRKYs （ Hb WRKY1 , Hb WRKY2 , Hb WRKY3 , Hb WRKY4 , Hb WRKY5 , Hb WRKY7 , Hb WRKY9 , Hb WRKY11 , Hb WRKY2 7 and HbWRKY75） in genotype ＇Reyan 7-33-97＇. The results showed that HbWRKY1 and HbWRKY4 were on the short arm of chromosome 9 with PDCS （ percent distance from centromere to the signal site） 57.38 and 4.57, re- spectively. The gene HbWRKY5 was on the long arm of chromosome 9 with PDCS 31.67. The genes HbWRKY2 ,Hb- WRKY3 ,HbWRKYT,HbWRKY9,HbWRKY11 and HbWRKY75 were mapped on the short arms of chromosomes 8,3,4,10,2 and 7, and their PDCS were 6. 00,12.30,4.40,45.21,5.74 and 26. 11, respectively. The gene Hb- WRKY27 was located on the long arm of chromosome 6, and its PDCS was 38.88. The positional relationship be- tween these genes and other mapped genes was further discussed.