中国北方稻田及其周边环境中根结线虫种类鉴定

Identification of root-knot nematode species from paddy field and surrounding environment in northern China

【目的】了解我国北方稻田及其周边环境中根结线虫的种类,为进一步制定水稻根结线虫病的防治策略提供参考。【方法】2020和2021年春季从我国河南、山东、宁夏、北京、吉林、黑龙江、新疆、甘肃、河北、辽宁、山西、陕西和内蒙古13个省(直辖市/自治区)的连片稻田、周围田埂、旱地等采集了1032份土样,每份土样与灭菌河沙混合后平均分成3等份分别放入花盆中,盆中一半播水稻一半播番茄,50 d后检测水稻或番茄根系是否有根结产生。挑取阳性样品根结中的雌成虫,制作会阴花纹玻片,对根结线虫种类进行形态鉴定;同时利用我国常见6种根结线虫特异性引物对土样中的根结线虫种类进行分子鉴定。【结果】生物测定结果显示,有119份土样能够引起水稻或番茄幼苗产生根结,总检出率为11.53%,其中宁夏回族自治区土样检出率最高,为33.33%。在根结线虫种类鉴定中发现,拟禾谷根结线虫(Meloidogyne graminicola)为北方水稻产区优势种,占鉴定样品的96.83%;花生根结线虫(M.arenaria)、北方根结线虫(M.hapla)、南方根结线虫(M.incognita)、象耳豆根结线虫(M.enterolobii)和爪哇根结线虫(M.javanica)分别占鉴定样品的84.13%,52.38%,31.75%,15.87%和3.17%。受1,2,3,4,5和6种根结线虫侵染的土样比例分别为11.11%,28.57%,28.57%,28.57%,3.18%和0%。其中最常见的为拟禾谷根结线虫、南方根结线虫、花生根结线虫和北方根结线虫混合侵染(23.81%),其次为拟禾谷根结线虫和花生根结线虫混合侵染(22.22%),再次为拟禾谷根结线虫、花生根结线虫和北方根结线虫混合侵染(15.87%),其他不同种类根结线虫混合侵染的田块比例不超过10.00%。【结论】根结线虫广泛分布于我国北方稻田及其周边环境中,其中拟禾谷根结线虫为优势种,象耳豆根结线虫也已适应低温由南向北扩散,今后应加大研究根结线虫在北方露地低温环境下的适应能力及扩散和危害风险,制定相应的防治措施。

【Objective】This study analyzed the distribution of root-knot nematodes(RKNs)in rice producing areas in northern China to provide strategies for nematode control.【Method】In spring of 2020 and 2021,1032 soil samples were collected from continuous paddy fields,surrounding field ridges and dry croplands from 13 provinces(municipality/autonomous region)in northern China,including Henan,Shandong,Ningxia,Beijing,Jilin,Heilongjiang,Xinjiang,Gansu,Hebei,Liaoning,Shanxi,Shaanxi and Inner Mongolia.Each soil sample was mixed with autosaved sand and divided into three sub-samples,and rice and tomato were used as baiting plants to form galls,which were checked after 50 d.Perineal patterns were made on selected adult females to generate morphological features and 6 pairs of specific primers were used to identify the RKN species as molecular tools.【Result】A total of 119 soil samples were able to form root galls on baiting roots of rice or tomato.The overall relevance ratio was 11.53%and Ningxia had the highest relevance ratio of 33.33%.In identified samples,Meloidogyne graminicola was the dominant species with relevance ratio of 96.83%.The relevance ratios of M.arenaria,M.hapla,M.incognita,M.enterolobii and M.javanica were 84.13%,52.38%,31.75%,15.87%and 3.17%,respectively.The ratios of PCR detected soil samples infested by 1,2,3,4,5 and 6 of RKN species were 11.11%,28.57%,28.57%,28.57%,3.18%and 0%,respectively.The mixture of M.graminicola,M.incognita,M.arenaria and M.hapla had the highest infection ration of 23.81%,followed by M.graminicola and M.arenaria mixture(22.22%)and M.graminicola,M.arenaria and M.hapla mixture(15.87%),while those of other mixtures were below 10.00%.【Conclusion】RKNs were widely distributed in paddy fields and surrounding environment in northern China,among which M.graminicola was the dominant species.M.enterolobii had also spread and adapted to low temperature from south to north.Strengthening the study of RKNs adaptability and formulating corresponding control measures are suggested.