Ni Chunhui, Zhang Run, Yang Sihua, Li Qian-Ying, Lu Yang, Yang Shuai, Xu Chunling, Xie Hui
South China Agricultural University College of Plant Protection, Guangzhou, Guangdong, China;
College of Plant Protection, South China Agricultural University, Guangzhou, China;
Plant Dis. 2025 Jun 23. doi: 10.1094/PDIS-03-25-0591-RE.
Sugarcane (Saccharum officinarum L.) is an important economic crop in tropical and subtropical countries and regions. During an investigation of crop nematodes in Guangdong, a new disease caused by a new species, Heterodera parasacchari n. sp. of the subfamily Heteroderinae was found on sugarcane. In this study, the new species is described, and its pathogenicity to sugarcane confirmed. The new species is characterized by having the cysts lemon-shaped with prominent neck and vulval cone, ambifenestrate, underbridge strongly developed with finger-like projections, bullae developed, fenestral width generally longer than fenestral length; second stage juveniles with well-developed stylet of 25.2 (23.7-26.9) μm and basal knobs concave and end projecting anteriorly, lateral field areolated with three incisures, tail 56.6 (47.5-64.8) μm long, hyaline region 32.4 (27.7-37.3) μm long and longer than stylet. The new species is close to H. sacchari in the Sacchari group of Heterodera genus base on morphologically and morphometrically. The phylogenetic trees, based on the analysis of the ITS-rRNA, 28S-rRNA D2-D3 region and the partial COI gene sequences, showed that the new species clustered with Sacchari group species but with separate species status. The results of pathogenicity tests indicated that H. parasacchari n. sp., can invade roots of sugarcane and reproduce in large numbers, resulting in thinner root systems, reduced lateral root, weakened and stunted plants, leaf chlorosis, and significant yield losses. A key to the species of Sacchari group is also provided in this study.
