Meloidogyne vitis, a new infecting nematode species on mulberry in Yunnan, China

Background Mulberry is an economically important sericulture crop, however, root-knot nematodes (RKNs) infection pose a serious threat to the production of mulberry. We found a high density RKNs parasitizing mulberry in Yunnan, China. In order to clarify the pathogenic species, the morphometric traits and measurements, rDNA/mtDNA-based phylogenetic relationships of this nematode and SCAR-PCR analysis were used to identify RKNs, and the mulberry healthy seedlings were inoculated artificially with second-stage juveniles to research pathogenicity. Results The perineal pattern of females is round to ovoid with a moderately high dorsal arch and two large and prominent phasmids, similar to Meloidogyne vitis . The morphological characteristics and morphometric values of females, second-stage juveniles and males were similar to M. vitis . The nucleotide sequence of rDNA ITS1-5.8S-ITS2, mtDNA coxI and coxII of this nematode were highly similar to M. vitis , with a similarity of more than 99%, and all were clustered within the same clade with those of M. vitis with a high support rate of 100%. Moreover, species identity was further confirmed using M. vitis -specific primers Mv-F/R, a single specific fragment of 174 bp was obtained. Artificial inoculation showed that the RKN isolated and purified from mulberry could complete its life history in the roots of healthy seedlings of mulberry, and produced typical root-knot and egg masses. Conclusions The RKN parasitizing in mulberry was confirmed as M. vitis based on the morphological features and molecular results. This is the first report of M. vitis attacking mulberry. M. vitis could infect and damage mulberry and may constitute a potential threat to mulberry production. The results of this study providing a theoretical basis for accurately identifying and implementing future effective and integrated nematodes management strategy to safeguard mulberry cultivation.