Transcriptomic and Metabolomic Responses of Rice Plants to Cnaphalocrocis medinalis Caterpillar Infestation.

Yuqi Wang,Qingsong Liu,Lixiao Du,Eric M Hallerman,Yunhe Li

doi:10.3390/insects11100705

Abstract

Simple SummaryThe transcriptomic and metabolomic differences in rice leaves after infestation by the rice leaf folder Cnaphalocrocis medinalis were investigated for better understanding of the mechanisms of rice defenses against this species. The results suggest that C. medinalis infestation can induce rapid and precise defense responses involved in many primary and secondary metabolic processes in rice leaves, and the jasmonic acid (JA)-dependent signaling pathway plays vital roles in the response of rice plants to this pest species. These results provide comprehensive insights into the defense system of rice to the rice leaf folder and may facilitate the development of insect-resistant rice varieties by identifying molecular targets for selection.Interactions between plants and insect herbivores are important determinants of plant productivity in cultivated and natural agricultural fields. The rice leaf folder (Cnaphalocrocis medinalis) causes tremendous damage to rice production in Asian countries. However, little information is available about how rice plants defend themselves against this destructive pest at molecular and biochemical levels. Here, we observed the transcriptomic and metabolomic differences in rice leaves after 0, 1, 6, 12, and 24 h of being fed by C. medinalis using RNA sequencing and metabolome profiling. Transcriptional analyses showed that gene expression responds rapidly to leaf folder infestation, with the most significant transcriptional changes occurring within 6 h after the initiation of feeding. Metabolite abundance changed more slowly than gene expression. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses indicated that the rice transcriptional response to infestation involved genes encoding protein kinases, transcription factors, biosynthesis of secondary metabolites, photosynthesis, and phytohormone signaling. Moreover, the jasmonic acid-dependent signaling pathway triggered by leaf folder herbivory played a vital role in rice defense against this pest. Taken together, our results provide comprehensive insights into the defense system of rice to this species and may inform the development of insect-resistant rice varieties.

Highlights

The intensive interactions between insect herbivores and their plant hosts during infestation can result in plant physiological disorders and even death, posing major threats to crop yield and Insects 2020, 11, 705; doi:10.3390/insects11100705 www.mdpi.com/journal/insectsInsects 2020, 11, 705 food security worldwide
The results showed that the expression of the selected eight jasmonic acid (JA) pathway-associated genes were consistent with those analyzed by RNA-seq (Figure S2), which indicated that the transcriptome datasets were sufficient for further analyses
differentially expressed genes (DEGs), we identified of three calmodulins (CaMs), 14 herbivory calmodulin-like proteins (CMLs), and 22 calciumdependent protein kinases (CDPKs) (Figure S4)

Summary

Introduction

The intensive interactions between insect herbivores and their plant hosts during infestation can result in plant physiological disorders and even death, posing major threats to crop yield and Insects 2020, 11, 705; doi:10.3390/insects11100705 www.mdpi.com/journal/insectsInsects 2020, 11, 705 food security worldwide. During the coevolutionary arms race between plants and insects, plant hosts have evolved multiple mechanisms of defense against insects, including direct and indirect responses. Signaling events triggered by herbivory are the initial response in plants and are responsible for triggering downstream signaling transduction pathways [1,2,6]. These signaling events mainly include depolarization of membrane potential, calcium flux, production of reactive oxygen species, and mitogen-activated protein kinase (MAPK)

Results

Discussion

Conclusion