Bruchid egg induced transcript dynamics in developing seeds of black gram (Vigna mungo).

Indrani K Baruah,Jagadale M.V,Bidyut Kumar Sarmah,Deba Jit Das,Debashis Panda,Sumita Acharjee,Priyabrata Sen

doi:10.1371/journal.pone.0176337

Indrani K Baruah, Jagadale M.V + Show 5 more

Open Access

https://doi.org/10.1371/journal.pone.0176337

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Journal: PloS one	Publication Date: Apr 27, 2017
Citations: 6	License type: CC BY 4.0

Affiliation: Assam Agricultural University

Abstract

Black gram (Vigna mungo) seeds are a rich source of digestible proteins, however, during storage these seeds are severely damaged by bruchids (Callosobruchus spp.), reducing seed quality and yield losses. Most of the cultivated genotypes of black gram are susceptible to bruchids, however, few tolerant genotypes have also been identified but the mechanism of tolerance is poorly understood. We employed Suppression Subtractive Hybridization (SSH) to identify specifically, but rarely expressed bruchid egg induced genes in black gram. In this study, Suppression Subtractive Hybridization (SSH) library was constructed to study the genes involved in defense response in black gram against bruchid infestation. An EST library of 277 clones was obtained for further analyses. Based on CAP3 assembly, 134 unigenes were computationally annotated using Blast2GOPRO software. In all, 20 defense related genes were subject to quantitative PCR analysis (qPCR) out of which 12 genes showed up-regulation in developing seeds of the pods oviposited by bruchids. Few major defense genes like defensin, pathogenesis related protein (PR), lipoxygenase (LOX) showed high expression levels in the oviposited population when compared with the non-oviposited plants. This is the first report on defense related gene transcript dynamics during the bruchid-black gram interaction using SSH library. This library would be useful to clone defense related gene(s) such as defensin as represented in our library for crop improvement.

Highlights

Black gram [Vigna mungo (L) Hepper] is widely grown in South and South Asia, including India
Reactive Oxygen Species (ROS) are associated with plant-insect interactions and there are several reports available on generation of ROS in response to stress. This acts as an indicator of defense response since there is crosstalk between ROS and hormone signaling during any stress [7]
The increment of the peroxidase activity which resulted in accumulation of H2O2 is evident in the response to bruchid beetle egg laying which lead to discolouration of the pod wall as well as the developing seeds inside in comparison to the green pod wall and seeds of non-oviposited control (Fig 1A and 1B)

Summary

Introduction

Black gram [Vigna mungo (L) Hepper] is widely grown in South and South Asia, including India. (Coleoptera: Bruchidae) causes considerable damage to both quantity and quality of black gram seeds during storage [1]. The primary infestation by bruchids begin in the field where insects lay eggs on pod wall and the larvae. Transcripts dynamics in black gram due to bruchid infestation bore inside the mature pods and eat developing seeds. The adult beetles emerge at the time of plant maturity or soon afterwards. The secondary infestation occurs in the storage where adults emerging soon after harvest oviposit on the dry seeds and later, larvae bore inside the seeds to complete their life cycle [2]. Bruchid infestation causes total destruction of the seeds within six months [3]. The defense response in black gram due to bruchid infestation has not yet been elucidated, there are reports on availability of both mild resistant genotypes and wild relatives with complete resistance to bruchids [4]

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