Transcriptional profile of genes involved in the production of terpenes and glyceollins in response to biotic stresses in soybean.

Talitta Regina Parmezan,Moisés De Aquino,Clara Beatriz Hoffmann Campo,Ricardo Vilela Abdelnor,John Pickett,Estela De Oliveira Nunes,Francismar Corrêa Marcelino-Guimarães,Kenia De Carvalho,Salvador Lima Brito Júnior,Michael Birkett

doi:10.1590/1678-4685-gmb-2019-0388

Abstract

Terpenes produced by plants comprise a diverse range of secondary metabolites, including volatile organic compounds (VOCs). Terpene VOC production may be altered after damage or by biological stimuli such as bacterial, fungal and insects, and subsequent triggering of plant defense responses. These VOCs originate in plants from two independent pathways: the mevalonate and the methylerythritol phosphate pathways, which utilize dimethylallyl and isopentenyl diphosphates to form the terpenoidal precursors. Phakopsora pachyrhizi fungi causes Asian soybean rust, limiting soybean production and resulting in losses of up to 80% if no control strategies are applied. By using a transcriptome datasets, we investigated the regulation of genes of the mevalonate pathway under different biotic stresses. We studied the impact of P. pachyrhizi infection in vivo expression profile of genes involved in terpenoid and glyceollin biosynthesis in genotypes harboring different resistance genes (Rpp), and across the infection cycle. In addition, we used UPLC and UPGC analysis to evaluate glyceollin and VOC production, respectively, to identify metabolites associated with soybean responses to pathogen infection. The regulation of soybean genes involved in terpene production was influenced by genotypes, depending on the Rpp gene, while glyceollin was induced in all genotypes. Furthermore, a sesquiterpene was identified as a potential marker associated with rust symptoms on soybean.

Highlights

Terpenes constitute the largest and most diversified class of secondary metabolites, including some volatile organic compounds (VOCs) formed from the combination of two or more isoprenyl units, with the molecular formula (C5H8O2)n
The contribution of the MVA pathway to glyceollin production occurs at the step catalyzed by isopentenyl diphosphate D-isomerase, which converts IPP into DMAPP, which can be transported from the cytoplasm to the chloroplast and elongate the pterocarpan skeleton formed from daidzein (Lygin et al, 2009)
We conducted an in silico analysis of soybean public transcriptome data available for 13 model genes identified in the MVA pathway (Table S3), aiming to infer the involvement of genes related to terpenes production, derivated by the MVA pathway, in soybean defense mechanisms in response to different biotic stresses, in particular by P. pachyrhizi

Summary

Introduction

Terpenes constitute the largest and most diversified class of secondary metabolites, including some volatile organic compounds (VOCs) formed from the combination of two or more isoprenyl units, with the molecular formula (C5H8O2)n These compounds constitute some signaling molecules in plants and are commonly produced in response to bacteria, fungi and insects infections (Mendgen et al, 2006; Huang et al, 2012; Pickett et al, 2012; Tamiru et al, 2012). The contribution of the MVA pathway to glyceollin production occurs at the step catalyzed by isopentenyl diphosphate D-isomerase, which converts IPP into DMAPP, which can be transported from the cytoplasm to the chloroplast and elongate the pterocarpan skeleton formed from daidzein (Lygin et al, 2009)

Methods

Results

Conclusion