The soybean cyst nematode, Heterodeara glycines, is a serious pathogen of soybean, and reported to be the host of a wide range of Fabaceae.  In the present study, the host specificity and reproductivity of two populations of H. glycines collected from soybean and tobacco were identified and characterized.  The comparative identity between β-1,4-endoglucanase, pectate lyase and chorismate mutase of H. glycines parasitizing on soybean and tobacco were 99, 97 and 98%, respectively.  The qRT-PCR analysis indicated that the expression of pectate lyase 2 gene was significantly higher in second-stage juveniles of H. glycines Henan population parasitizing on tobacco than that of H. glycines Shanxi population parasitizing on soybean.  In addition, the pectic acid content of cell wall was significantly higher (45%) in the roots of tobacco than the roots of soybean.  Our results indicate that the changes in transcript parasitism genes may be a result of long-term evolution illustrating how a plant-parasitic nematode adapts to the host environment for optimal infestation and survival.

 

The rice root-knot nematode Meloidogyne graminicola is a severe pest of rice.  In China, it was first reported from Hainan Province, and later from several other provinces.  In the present study, a rice root-knot nematode population found from the rice cultivation areas of Zhejiang Province, China is characterized via molecular analysis using internal transcribed spacer (ITS) and cytochrome c oxidase subunit II (coxII)-16S rRNA genes and scanning electron microscopy (SEM) observations of males and the second-stage juveniles.  Morphometric data and molecular sequence comparisons for all M. graminicola populations occurring in China are also provided.  The overall morphology of M. graminicola found in Zhejiang match well with the original description, though males have a slightly longer body and stylet, and a shorter tail, while the second-stage juvenile is also slightly longer than in the original description.  This is the first report of M. graminicola from Zhejiang.  Phylogenetic studies based on coxII suggest that all the Chinese populations belong to Type B.  This study expands knowledge of the increasing distribution and phylogenetic relationships of M. graminicola that occur in China.