Comparative Transcriptome Analysis of Pine Trees Treated with Resistance-Inducing Substances against the Nematode Bursaphelenchus xylophilus.

Jungwook Park,Ae Ran Park,Namgyu Kim,Hee Won Jeon,Young-Su Seo,Junheon Kim,Gil Han,Jin-Cheol Kim,Hyejung Jung,Hyun-Hee Lee

doi:10.3390/genes11091000

Abstract

The pinewood nematode (PWN) Bursaphelenchus xylophilus causes pine wilt disease, which results in substantial economic and environmental losses across pine forests worldwide. Although systemic acquired resistance (SAR) is effective in controlling PWN, the detailed mechanisms underlying the resistance to PWN are unclear. Here, we treated pine samples with two SAR elicitors, acibenzolar-S-methyl (ASM) and methyl salicylic acid (MeSA) and constructed an in vivo transcriptome of PWN-infected pines under SAR conditions. A total of 252 million clean reads were obtained and mapped onto the reference genome. Compared with untreated pines, 1091 and 1139 genes were differentially upregulated following the ASM and MeSA treatments, respectively. Among these, 650 genes showed co-expression patterns in response to both SAR elicitors. Analysis of these patterns indicated a functional linkage among photorespiration, peroxisome, and glycine metabolism, which may play a protective role against PWN infection-induced oxidative stress. Further, the biosynthesis of flavonoids, known to directly control parasitic nematodes, was commonly upregulated under SAR conditions. The ASM- and MeSA-specific expression patterns revealed functional branches for myricetin and quercetin production in flavonol biosynthesis. This study will enhance the understanding of the dynamic interactions between pine hosts and PWN under SAR conditions.

Highlights

Pine trees from the genus Pinus are widely distributed in a variety of environments, ranging from areas at sea level to mountainous areas and from some of the coldest to the hottest environments on earth [1,2,3]
The conversion of naringenin to dihydrokaempferol is the initial step in flavonol biosynthesis and it has been shown that the seven genes of F30 50 H, which catalyses the conversion of dihydrokaempferol to myricetin, were highly expressed in response to the ASM treatment, whereas these genes showed downregulated or non-significant expression in response to the methyl salicylic acid (MeSA) treatment
The conversion of naringenin to dihydrokaempferol is the initial step in flavonol biosynthesis and it has been shown that the seven genes of F3′5′H, which catalyses the conversion of dihydrokaempferol to myricetin, were highly expressed in response to the ASM treatment, whereas these genes showed downregulated or non-significant expression in response to the MeSA treatment

Summary

Introduction

Pine trees from the genus Pinus are widely distributed in a variety of environments, ranging from areas at sea level to mountainous areas and from some of the coldest to the hottest environments on earth [1,2,3]. Pine forests are among the most valuable resources, with respect to timber, fuel, and various wood products [4,5,6]; native pine forests provide important habitats or source of. In recent decades, pine trees have suffered from epidemic attacks of pine wilt disease (PWD), and their populations have reduced markedly since the 1960s [7,8]. Subsequent to its initial detection in Japan at the beginning of the 20th century [9], PWD spread rapidly throughout a number of East. In Japan, some 700,000 m3 of pine forests are infected by PWD each year [14], whereas in the 10 years between 2003 and 2013, China lost USD 20 billion as a consequence of the mass dieback of 1 million ha of pine forests in 16 provinces [15]

Methods

Results

Discussion

Conclusion