Objective MicroRNA (miRNA) has the function of silence target mRNA expression, which is considered as a negative role in the regulation of gene expression. This study aims to reveal the potential expression correlation between miRNA and mRNA from needle leaves of Pinus massoniana with Bursaphelenchus xylophilus infestation, which helps to further indicate the mechanism of host plant in response to the pathogen infestation, and to obtain the particular miRNA and the target mRNA that involved in the regulation of masson pine resistance to pine wilt disease.

Method Expression pools of miRNA and mRNA from P. massoniana with B. xylophilus infestation for 1, 2, and 3 d, which were generated using RNA-seq in our previous studies, were used as materials. The different expression profiles of miRNA or mRNA from P. massoniana with B. xylophilus infestation for different days were figured using STEM (Short Time-series Expression Miner) software, and method of Spearman Rank Correlation was employed to comparatively analyze the miRNA and mRNA expression profiles of P. massoniana.

Result Two significant expression profiles were generated from the miRNA pools of P. massoniana with B. xylophilus infestation for 1, 2, and 3 d, whilst 8 significant profiles were generated from that of mRNA pools. Fifteen miRNAs were considered as candidates that obviously represented correlation with twelve mRNAs from the expression pools. The reverse expression profiles between the mRNA and miRNA validate the bio-function of transcriptional silence from miRNA to the target mRNA. The miRNA-targeted mRNA encodes ACRE, CC-NBS-LRR resistance-like gene, etc. These genes play roles in plant pathogen recognition.

Conclusion It was clear that the infestation of B. xylophilus resulted in various expression profiles of miRNA and mRNA from the P. massoniana, and numbers of miRNA presented a reverse expression pattern in comparison with target mRNA. Among these miRNAs, several of them were speculated that function in silenced expression of genes involved with pathogen recognition.