JIA-2018-09

Journal of Integrative Agriculture 2018, 17(9): 2066–2073 RESEARCH ARTICLE Available online at www.sciencedirect.com ScienceDirect The biotypes and host shifts of cotton-melon aphids Aphis gossypii in northern China ZHANG Shuai, LUO Jun-yu, WANG Li, WANG Chun-yi, LÜ Li-min, ZHANG Li-juan, ZHU Xiang-zhen, CUI Jin-jie State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, P.R.China Abstract Aphis gossypii is a globally distributed species and therefore has a highly variable life cycle. Populations of A . gossypii in northern China exhibit greater genotypic diversity and a broader host range, yet the details of life cycles of different biotypes is still unclear. In this study, the Cytb and 16S gene regions of A . gossypii collected from 5 common summer hosts and 4 primary hosts were analyzed. A total of 57 haplotypes were obtained from 1 046 individual A . gossypii sequences. The sequence included 44 variable sites, 27 of which were parsimony informative sites and 17 of which were singleton variable sites. The most frequent 3 haplotypes were found in 896 individuals, representing a total of 85.7% of all individuals and 36 haplotypes were found in 1 individual. A neighbor-joining tree was constructed using 21 haplotypes that were found in more than 2 individuals. Considering the individual host plant, 5 biotypes were identified. Type 1 corresponded exactly to the cucurbit host-race and the other 4 biotypes were found as cotton host-races. Type 3 was the most abundant biotype in cotton fields in northern China. Keywords: cotton-melon aphid, Cytb and 16S genes, haplotype, biotype, cotton field Economic losses caused by this aphid result from its direct physical damage due to extraction of carbohydrates and amino acids from the plant phloem, and also due to spreading of plant viral diseases (Chan et al. 1991). In northern China, the species is an important insect pest of cotton and has breakouts 2 times each year during the cotton seedling stage and during summer (Li et al. 2013). A. gossypii that specializes in cucurbits is by far the most serious pest of Cucurbitaceae crops worldwide (Thomas et al. 2016). A. gossypii is a globally distributed species and thus has a highly variable life cycle. It has been described as holocyclic in China, Japan, Korea, India, and the USA, where there are very cold winters (Margaritopoulos et al. 2007). In most places where it is found, including in Europe and Africa, it reproduces continuously by apomictic parthenogenesis Received 6 June, 2017 Accepted 13 October, 2017 ZHANG Shuai, E-mail: zhsjwl@163.com; Correspondence CUI Jin-jie, Tel: +86-372-2562217 , E-mail: aycuijinjie@163.com © 2018 CAAS. Publishing services by Elsevier B.V. All rights reserved. doi: 10.1016/S2095-3119(17)61817-3 1. Introduction The cotton-melon aphid, Aphis gossypii Glover, is a mosaic of sympatric host-races (Carletto et al. 2009b). This pest colonizes more than 600 plant species, including many important crops such as cotton, cucurbits, citrus, aubergine, potato, and okra (Blackman and Eastop 2000).