Janique Solene, Sriratanasak Wantana, Ketsuwan Kulchana, Jairin Jirapong, Jeratthitikul Ekgachai
Animal Systematics and Molecular Ecology Laboratory, Department of Biology, Faculty of Science, Mahidol University, Bangkok, 10400, Thailand.
Bureau of Rice Research and Development, Rice Department, Chatuchak, Bangkok, 10900, Thailand.
Genetica. 2017 Feb;145(1):37-49. doi: 10.1007/s10709-016-9944-8. Epub 2017 Jan 9.
The Asian rice gall midge (RGM) Orseolia oryzae (Wood Mason) (Diptera: Cecidomyiidae) is a major pest of rice, leading to yield losses in Thailand and many Asian countries. Despite an increasing number of reported midge outbreaks and the presence of many susceptible rice varieties, only a few studies have focused on the genetic variation of the midges. Therefore, we analyzed the phylogeography among Thai RGM populations covering north, northeast and central Thailand. Two mitochondrial DNA genes, cytochrome C oxidase I (COI) and 12S, and a non-coding repeat region (RR) situated just before COI were amplified. Overall, the haplotype diversity for COI and 12S genes of the Thai population was high, but the nucleotide diversity was quite low. Altogether, the phylogenetic tree and pairwise F values indicated that Thai RGM populations recently expanded and were homogeneously distributed throughout the country, except for some populations in the north, which most likely became recently isolated from the main population. Two non-coding repeat motifs, that were recently observed in the mitogenome of RGM in India, were absent in Thai populations and replaced by an 89 bp non-coding sequence. Tandem nucleotide repeats of the sequence TA were also observed. The repeat copy number varied from 2 to 11 and was not correlated with geographical repartition of the midge. Finally, COI barcoding divergence between Indian and Thai populations was high (6.3% in average), giving insights into the potential existence of an RGM species complex in Asia.
亚洲稻瘿蚊（RGM）稻瘿蚊（Wood Mason）（双翅目：瘿蚊科）是水稻的主要害虫，在泰国和许多亚洲国家导致产量损失。尽管报告的稻瘿蚊爆发事件越来越多，且存在许多易感水稻品种，但只有少数研究关注稻瘿蚊的遗传变异。因此，我们分析了泰国北部、东北部和中部的RGM种群之间的系统地理学。扩增了两个线粒体DNA基因，即细胞色素C氧化酶I（COI）和12S，以及位于COI之前的一个非编码重复区域（RR）。总体而言，泰国种群COI和12S基因的单倍型多样性较高，但核苷酸多样性相当低。总的来说，系统发育树和成对F值表明，泰国RGM种群最近有所扩张，并且在全国范围内分布均匀，除了北部的一些种群，这些种群很可能最近与主要种群隔离。泰国种群中不存在最近在印度RGM的有丝分裂基因组中观察到的两个非编码重复基序，取而代之的是一个89 bp的非编码序列。还观察到序列TA的串联核苷酸重复。重复拷贝数从2到11不等，与稻瘿蚊的地理分布无关。最后，印度和泰国种群之间的COI条形码差异很高（平均为6.3%），这为亚洲存在RGM物种复合体的可能性提供了线索。
