Genome-Wide Analysis of Cotton miRNAs During Whitefly Infestation Offers New Insights into Plant-Herbivore Interaction.

Jianying Li,Qinghua Zhang,Luo Chen,Shahid Mansoor,Xianlong Zhang,Maojun Wang,Qiongqiong Wang,Shuangxia Jin,J Joe Hull,Sijia Liang

doi:10.3390/ijms20215357

Abstract

Although the regulatory function of miRNAs and their targets have been characterized in model plants, a possible underlying role in the cotton response to herbivore infestation has not been determined. To investigate this, we performed small RNA and degradome sequencing between resistant and susceptible cotton cultivar following infestation with the generalist herbivore whitefly. In total, the 260 miRNA families and 241 targets were identified. Quantitative-PCR analysis revealed that several miRNAs and their corresponding targets exhibited dynamic spatio-temporal expression patterns. Moreover, 17 miRNA precursors were generated from 29 long intergenic non-coding RNA (lincRNA) transcripts. The genome-wide analysis also led to the identification of 85 phased small interfering RNA (phasiRNA) loci. Among these, nine PHAS genes were triggered by miR167, miR390, miR482a, and two novel miRNAs, including those encoding a leucine-rich repeat (LRR) disease resistance protein, an auxin response factor (ARF) and MYB transcription factors. Through combined modeling and experimental data, we explored and expanded the miR390-tasiARF cascade during the cotton response to whitefly. Virus-induced gene silencing (VIGS) of ARF8 from miR390 target in whitefly-resistant cotton plants increased auxin and jasmonic acid (JA) accumulation, resulting in increased tolerance to whitefly infestation. These results highlight the provides a useful transcriptomic resource for plant-herbivore interaction.

Highlights

Cotton (Gossypium spp.) is a widely cultivated economic crop utilized for its fiber and oil-yielding capabilities that are negatively impacted by both abiotic and biotic stresses
To explore the relationship between miRNA and short interfering RNAs (siRNA) abundance and the different cotton cultivars’ responses to whitefly infestation, we constructed sRNA libraries with three biological replicates per sample type from the HR and ZS plants infested with adult whiteflies for 24 h and mock infested plants (Table 1)
The expression of AP2/B3 did not dramatically change, though the expression of the phasiRNAs were downregulated and the phasiRNAs were diminished after whitefly infestation. These results suggest that cascades of long intergenic non-coding RNA (lincRNA), miRNAs, PHAS and their targets are fundamental in plant pathways activated in response to herbivore infestation

Summary

Introduction

Cotton (Gossypium spp.) is a widely cultivated economic crop utilized for its fiber and oil-yielding capabilities that are negatively impacted by both abiotic and biotic stresses. Transgenic cotton expressing Bacillus thuringiensis (Bt) cry toxins have been used successfully to control lepidopteran pests, including Helicoverpa armigera and Pectinophora gossypiella, similar technology has yet to be fully developed for activity against phloem-feeding pests, such as whitefly, aphid, and leafhopper [2,3,4]. (Bemisia tabaci) is a destructive pest of many agronomically important crops, such as tobacco, tomato, lettuce and cotton, and causes extensive crop damage by directly sucking phloem sap and vectoring diverse viruses [5]. Shukla et al (2016) identified a candidate protein from edible fern (T. macrodonta) that was toxic to whitefly [6]. Zhu et al previously assessed the susceptibility of 400 elite cotton lines to whitefly infestation and identified 42 lines between resistance and the susceptibility spectrum [7]

Methods

Results

Discussion

Conclusion