Histopathology combined with transcriptome analyses reveals the mechanism of resistance to Meloidogyne incognita in Cucumis metuliferus.
Root-knot nematodes (Meloidogyne spp.) cause serious threat to cucumber production. Cucumis metuliferus, a relative of cucumber, is reported to be resistant to Meloidogyne incognita, yet the underlying resistance mechanism remains unclear. In this study, the response of resistant C. metuliferus accession PI482443 following nematode infection was studied in comparison with susceptible C. sativus cv. Jinlv No.3. Roots of selected Cucumis seedings were analysed using histological and biochemical techniques. Transcriptome changes of the resistance reaction were investigated by RNA-seq. The results showed that penetration and development of the nematode in resistant plants were reduced when compared to susceptible plants. Infection of a resistant genotype with M. incognita resulted in a hypersensitive reaction. The induction of phenylalanine ammonia lyase and peroxidase activities after infection was greater in resistant than susceptible roots. Several of the most relevant genes for phenylpropanoid biosynthesis, plant hormone signal transduction, and the plant-pathogen interaction pathway that are involved in resistance to the nematode were significantly altered. The resistance in C. metuliferus PI482443 to M. incognita was associated with reduced nematode penetration, retardation of nematode development, and hypersensitive necrosis. The expression of genes resulting in the deposition of lignin, toxic compounds synthesis, cell wall reinforcement, suppression of nematode feeding and resistance protein accumulation, and activation of several transcription factors might all contribute to the resistance response to the pest. These results may lead to a better understanding of the resistance mechanism and aid in the identification of potential targets resistant to pests for cucumber improvement.
Institute of Vegetables, Gansu Academy of Agricultural Sciences, Scientific Observations Experiment Station of Vegetables, Ministry of Agriculture in the Northwest of China, Lanzhou 730070, China. Electronic address: ydy287@163.com.
De-You
DY
Ye
Institute of Plant Protection, Gansu Academy of Agricultural Sciences, Lanzhou 730070, China.
Yong-Hong
YH
Qi
Institute of Fruit and Floriculture Research, Gansu Academy of Agricultural Sciences, Lanzhou 730070, China.
Su-Fang
SF
Cao
Institute of Vegetables, Gansu Academy of Agricultural Sciences, Scientific Observations Experiment Station of Vegetables, Ministry of Agriculture in the Northwest of China, Lanzhou 730070, China.
Bing-Qiang
BQ
Wei
Institute of Vegetables, Gansu Academy of Agricultural Sciences, Scientific Observations Experiment Station of Vegetables, Ministry of Agriculture in the Northwest of China, Lanzhou 730070, China.
Hua-Sheng
HS
Zhang
D000818:Animals; D028462:Cucumis / Q000235:genetics* / Q000378:metabolism / Q000469:parasitology*; D060467:Disease Resistance / Q000235:genetics*; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant; D005838:Genotype; D006790:Host-Parasite Interactions / Q000235:genetics; D058977:Molecular Sequence Annotation; D059828:Plant Cells; D010935:Plant Diseases / Q000469:parasitology*; D010937:Plant Growth Regulators / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology / Q000201:enzymology / Q000469:parasitology; D017423:Sequence Analysis, RNA; D015398:Signal Transduction; D014157:Transcription Factors; D059467:Transcriptome; D014431:Tylenchoidea / Q000472:pathogenicity*
D010937:Plant Growth Regulators; D014157:Transcription Factors
Cucumis metuliferus; Histopathology; Meloidogyne incognita; Resistance; Transcriptome