The AL-ao379 gene plays a role in promoting the invasion stage of Bursaphelenchus xylophilus trapped by Arthrobotrys cladodes

Abstract

BACKGROUND: Nematode-trapping fungi can be used to develop specialized trapping devices to trap and kill nematodes, and the use of such fungi, with high efficiency and no toxicity to the environment, as biological control agents is very promising. Moreover, an understanding of the trap formation mechanism and the discovery of key pathogenic genes can help improve the efficacy of biocontrol agents. RESULTS: In this study, we used RNA-Seq to reveal the transcriptome characteristics of Arthrobotrys cladodes under Bursaphelenchus xylophilus induction. When many traps were observed to be produced, mycelia were collected and subjected to differential expression analysis. Differentially expressed genes were screened. AL-ao379 was identified by BLAST analysis and cloned by PCR. The results indicated that the AL-ao379 CDS was 1206 bp and encoded 402 amino acids. The expression of the AL-ao379 gene in different trapping stages was further compared by RT‒PCR. It was verified that the expression of the chitinase gene AL-ao379 increased significantly with the approach of the invasion stage and then decreased after reaching the highest levels in the invasion and predigestion stage. CONCLUSION: The chitinase gene AO-379 has been shown to affect the trapping responses of A. oligospora in soils, but to our knowledge, the effect of the chitinase on arboreal nematode-trapping fungi has not been previously reported. Our results demonstrated that the AL-ao379 gene was a key gene and a potential control target involved in trapping and that it was significantly expressed in invasion stages. In addition, we proposed a model of infestation mechanism of B. xylophilus trapping by arboreal nematode-trapping fungi.