Effects of Elevated Temperature on the Susceptibility of Capsicum Plants to Capsicum Chlorosis Virus Infection.

Wei-An Tsai,Neena Mitter,Jonathan R Shafiei-Peters,Ralf G Dietzgen

doi:10.3390/pathogens11020200

Wei-An Tsai, Neena Mitter + Show 2 more

Open Access

https://doi.org/10.3390/pathogens11020200

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Abstract

Capsicum, an important vegetable crop in Queensland, Australia, is vulnerable to both elevated temperatures and capsicum chlorosis virus (CaCV). Thus, it is imperative to understand the genetic responses of capsicum plants (Capsicum annuum) to CaCV under elevated temperature conditions. Here, we challenged susceptible plants (cv. Yolo Wonder) with CaCV and investigated the effects of elevated temperature on symptom expression, the accumulation of virus-derived short interfering RNA (vsiRNA) and viral RNA, and the expression of plant defense-associated genes. CaCV-inoculated plants initially showed more severe symptoms and higher viral concentrations at a higher temperature (HT, 35 °C) than at ambient temperature (AT, 25 °C). However, symptom recovery and reduced viral RNA accumulation were seen in the CaCV-infected plants grown at HT at later stages of infection. We also observed that HT enhanced the accumulation of vsiRNAs and that, concurrently, RNA interference (RNAi)-related genes, including Dicer-like2 (DCL2), DCL4, RNA-dependent RNA polymerase 1 (RdRp1), RdRp6, and Argonaute2 (AGO2), were upregulated early during infection. Moreover, continuous high levels of vsiRNAs were observed during later stages of CaCV infection at HT. Overall, our investigation suggests that HT facilitates CaCV replication during early infection stages. However, this appears to lead to an early onset of antiviral RNA silencing, resulting in a subsequent recovery from CaCV in systemic leaves.

Highlights

Global food production is projected to become increasingly insecure due to future climate change scenarios [1]
Four-week-old plants were inoculated with capsicum chlorosis virus (CaCV), half of the plants were transferred to high temperature (HT), and half remained at ambient temperature (AT)
A recovery phenotype manifested as mild systemic symptoms in newly emerged leaves in 3 out of 8 CaCV-infected plants grown at HT at 10 dpi, while this recovery phenotype was seen later in the other 5 CaCV-infected plants grown at HT by 15, 18, or 21 dpi (Figure 1 F)

Summary

Introduction

Global food production is projected to become increasingly insecure due to future climate change scenarios [1]. Warmer temperatures are one of the vital climate stressors that influence food security globally [1]. Rising temperatures can cause crop production losses by directly interfering with plant physiological processes, plant development, and reproduction [2,3,4]. This has been seen in several crops, such as bean (Phaseolus vulgaris L.) [5], cowpea (Vigna unguiculata (L.) Walp.) [6], corn (Zea mays L.) [7], tomato An increase in temperature influences crop yield indirectly through changes in plant disease progression or insect pest biology [12,13,14,15,16]

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