Serendipita indica modulates expression of arginine metabolism genes during colonization of Arabidopsis thaliana roots

Shahbaz Anwar

doi:10.19045/bspab.2018.700203

Abstract

Abstract Endophytic fungus Serendipita indica belongs to the order Sebacinales. It is an extremely versatile root endophyte colonizing more than 150 different plant species including the model plant Arabidopsis thaliana. Colonization of S. indica triggers enhanced growth, early flowering, increase in seed content, alteration of secondary metabolite pathways and adaption to different biotic and abiotic stresses. This is why this fungus got ample attention by the plant researchers. In this study, we report modulation in expression of argininosuccinate synthase (AS), argininosuccinate lyase (AL) and arginase 2 (ARGAH2) genes in A. thaliana as a result of S. indica colonization. Similarly, expression of GUS reporter gene driven by AS and ARGAH2 promoters in roots was altered. AS, AL and ARGAH2 genes were down-regulated at early stage of root colonization i.e at 3 days post inoculation (dpi), with a subsequent up-regulation at later stages (7 and 14 dpi). Other arginine catabolism genes, Arginine decarboxylase-1 (ADC1), Arginine decarboxylase-2 (ADC2) and Pyrroline-5-carboxylate reductase (P5CR) were strongly up-regulated at later stages of S. indica colonization. Our findings show significant changes in expression of several important genes in arginine metabolic pathway upon S. indica colonization. These changes are very specific and strongly depend on the colonization phase of the fungus. Keywords: AL; ARGAH1; ARGAH2; AS; Arginine metabolism; GUS; Quantitative RT-PCR; Serendipita indica http://dx.doi.org/10.19045/bspab.2018.700203

Highlights

Introduction cause severe damage to environmentUse of Abiotic and biotic stresses are the major biological agents instead of chemical causes of crop losses throughout the world.treatments is gaining more attentionThey primarily include unfavorable climate and importance
This work was conducted to study involvement of genes connected to this pathway during S. indica colonization of A. thaliana roots
argininosuccinate lyase (AL) was strongly down-regulated at 3 dpi, which might result in decreased arginine biosynthesis in S. indica colonized roots at early colonization phase

Summary

Introduction

Introduction cause severe damage to environmentUse of Abiotic and biotic stresses are the major biological agents instead of chemical causes of crop losses throughout the world.treatments is gaining more attentionThey primarily include unfavorable climate and importance. Use of Abiotic and biotic stresses are the major biological agents instead of chemical causes of crop losses throughout the world. They primarily include unfavorable climate and importance. Mycorrhizae are already conditions, different plant diseases and plant established as beneficial associations of fungi pests. One commonly used solution to cope with plants increasing their growth and with these stresses is the high chemical input production. Endophytic arbuscular to increase the plant production [1]. Mycorrhizal fungi (AMF) are proven to these soil and plants treatments enhance abiotic stress tolerance. Arginine is catabolized to polyamines in many reactions, where the first step involves the

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