Wang Chih-Li, Malkus Arkadiusz, Zuzga Sabina M, Chang Pi-Fang Linda, Cunfer Barry M, Arseniuk Edward, Ueng Peter P
Department of Plant Protection, Fengshan Tropical Horticultural Experiment Station, Agricultural Research Institute, Kaohsiung 830, Taiwan.
Genome. 2007 Jun;50(6):595-609. doi: 10.1139/g07-038.
Phaeosphaeria species are important causal agents of Stagonospora leaf blotch diseases in cereals. In this study, the nucleotide sequence and deduced polypeptide of the trifunctional histidine biosynthesis gene (his) are used to investigate the phylogenetic relationships and provide molecular identification among cereal Phaeosphaeria species. The full-length sequences of the his gene were obtained by PCR amplification and compared among cereal Phaeosphaeria species. The coding sequence of the his gene in wheat-biotype P. nodorum (PN-w) was 2697 bp. The his genes in barley-biotype P. nodorum (PN-b), two P. avenaria f. sp. triticea isolates (homothallic Pat1 and Pat3), and Phaeosphaeria species from Polish rye and dallis grass were 2694 bp. The his gene in heterothallic isolate Pat2, however, was 2693 bp because the intron had one fewer base. In P. avenaria f. sp. avenaria (Paa), the his gene was only 2670 bp long. The differences in the size of the his gene contributed to the variation in amino acid sequences in the gap region located between the phosphoribosyl-ATP pyrophosphohydrolase and histidinol dehydrogenase sub-domains. Based on nucleotide and deduced amino acid sequences of the his gene, Pat1 was not closely related to either PN-w or the Paa clade. It appears that rates of evolution of the his gene were fast in cereal Phaeosphaeria species. The possible involvement of meiotic recombination in genetic diversity of the his gene in P. nodorum is discussed.
球腔菌属物种是谷物中壳针孢叶斑病的重要病原体。在本研究中，利用三功能组氨酸生物合成基因（his）的核苷酸序列和推导的多肽来研究谷物球腔菌属物种之间的系统发育关系并提供分子鉴定。通过PCR扩增获得his基因的全长序列，并在谷物球腔菌属物种之间进行比较。小麦生物型小麦壳针孢（PN-w）中his基因的编码序列为2697 bp。大麦生物型小麦壳针孢（PN-b）、两个小麦条斑病菌分离株（同宗配合的Pat1和Pat3）以及来自波兰黑麦和毛线稷的球腔菌属物种中的his基因均为2694 bp。然而，异宗配合分离株Pat2中的his基因长度为2693 bp，因为内含子少了一个碱基。在燕麦条斑病菌（Paa）中，his基因仅长2670 bp。his基因大小的差异导致了位于磷酸核糖基-ATP焦磷酸水解酶和组氨醇脱氢酶亚结构域之间的间隙区域氨基酸序列的变化。基于his基因的核苷酸和推导的氨基酸序列，Pat1与PN-w或Paa进化枝均无密切关系。看来his基因在谷物球腔菌属物种中的进化速度很快。本文还讨论了减数分裂重组可能参与小麦壳针孢中his基因遗传多样性的情况。
