Proteo-metabolomic investigation of transgenic rice unravels metabolic alterations and accumulation of novel proteins potentially involved in defence against Rhizoctonia solani

Subhasis Karmakar,Swapan K. Datta,Kaushik Das,Karabi Datta,Sailendra Nath Sarkar,Kutubuddin Ali Molla,Dipak Gayen

doi:10.1038/s41598-019-46885-3

Abstract

The generation of sheath blight (ShB)-resistant transgenic rice plants through the expression of Arabidopsis NPR1 gene is a significant development for research in the field of biotic stress. However, to our knowledge, regulation of the proteomic and metabolic networks in the ShB-resistant transgenic rice plants has not been studied. In the present investigation, the relative proteome and metabolome profiles of the non–transformed wild-type and the AtNPR1-transgenic rice lines prior to and subsequent to the R. solani infection were investigated. Total proteins from wild type and transgenic plants were investigated using two-dimensional gel electrophoresis (2-DE) followed by mass spectrometry (MS). The metabolomics study indicated an increased abundance of various metabolites, which draws parallels with the proteomic analysis. Furthermore, the proteome data was cross-examined using network analysis which identified modules that were rich in known as well as novel immunity-related prognostic proteins, particularly the mitogen-activated protein kinase 6, probable protein phosphatase 2C1, probable trehalose-phosphate phosphatase 2 and heat shock protein. A novel protein, 14–3–3GF14f was observed to be upregulated in the leaves of the transgenic rice plants after ShB infection, and the possible mechanistic role of this protein in ShB resistance may be investigated further.

Highlights

Rice sheath blight (ShB) is the second most-devastating and widespread disease reported from almost all the rice-cultivating nations, with an estimated annual yield loss of up to 50%1,2
Previous studies have demonstrated that the Arabidopsis NPR1 gene serves as a key regulator in salicylic acid (SA) signalling pathway, leading to systemic acquired resistance (SAR)[10,11,12]
AtNPR1 expression in the transgenic rice leads to enhanced resistance against the Sheath blight (ShB) disease (Supplementary Fig. S2)

Summary

Introduction

Rice sheath blight (ShB) is the second most-devastating and widespread disease reported from almost all the rice-cultivating nations, with an estimated annual yield loss of up to 50%1,2. Our previous studies in rice variety Pusa Sugandh-2 and Jaldi-13 have showed the effectivity of AtNPR1 in enhancing ShB disease resistance[20,21]. These studies demonstrated the effectiveness of the transgenic expression of the AtNPR1 gene in controlling broad spectrum pathogens. In order to understand the underlying mechanism of resistance of these transgenic rice plants, it was decided to study protein and metabolic profile that are altered in response to the R solani infection. The present study provides insights into the rice-R. solani interaction and a basic understanding of the proteomic and metabolomic alternations in the transgenic rice plants in order to confer enhanced resistance

Methods

Results

Conclusion