Agronomical, biochemical and histological response of resistant and susceptible wheat and barley under BYDV stress.

Sergey Shabala,Holger Meinke,Ibrahim Ahmed,Meixue Zhou,Philip Larkin,Hongliang Hu,Shormin Choudhury

doi:10.7717/peerj.4833

Sergey Shabala, Holger Meinke + Show 5 more

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https://doi.org/10.7717/peerj.4833

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Abstract

Barley yellow dwarf virus-PAV (BYDV-PAV) is one of the major viruses causing a widespread and serious viral disease affecting cereal crops. To gain a better understanding of plant defence mechanisms of BYDV resistance genes (Bdv2 and RYd2) against BYDV-PAV infection, the differences in agronomical, biochemical and histological changes between susceptible and resistant wheat and barley cultivars were investigated. We found that root growth and total dry matter of susceptible cultivars showed greater reduction than that of resistant ones after infection. BYDV infected leaves in susceptible wheat and barley cultivars showed a significant reduction in photosynthetic pigments, an increase in the concentration of reducing sugar. The protein levels were also low in infected leaves. There was a significant increase in total phenol contents in resistant cultivars, which might reflect a protective mechanism of plants against virus infection. In phloem tissue, sieve elements (SE) and companion cells (CC) were severely damaged in susceptible cultivars after infection. It is suggested that restriction of viral movement in the phloem tissue and increased production of phenolic compounds may play a role in the resistance and defensive mechanisms of both Bdv2 and RYd2 against virus infection.

Highlights

Barley yellow dwarf virus-PAV (BYDV-PAV) is transmitted by aphids and has been recognized as one of the most serious viral pathogens of the Luteovirus genus that systemically infects cereal crops (Jiménez-Martínez et al, 2004)
The virus extinction value was the highest in BYDV inoculated susceptible barley plant (Flagship) followed by susceptible wheat (Revenue) and the lowest value was detected in resistant wheat variety (Manning) (Fig. 3), suggesting that both the Ryd2 gene of barley and the Bdv2 gene of wheat reduced the viral load
The reduced photosynthesis capacity caused by reduced content of photosynthetic pigments contributes to the decrease in biomass production, which is shown in our studies as well as previous reports on BYDV infected cereals (Bukvayová et al, 2006)

Summary

Introduction

Barley yellow dwarf virus-PAV (BYDV-PAV) is transmitted by aphids and has been recognized as one of the most serious viral pathogens of the Luteovirus genus that systemically infects cereal crops (Jiménez-Martínez et al, 2004). The use of resistant or tolerant varieties is an effective solution and economical method for controlling BYD disease (Ordon et al, 2004). Wheat lines containing Bdv gene showed less yellowing and lower viral. Barley cultivars containing Ryd have lower virus titre after BYDV infection, which leads to less visual symptom and grain yield reduction (Beoni et al, 2016). Many plant defence pathways can be activated or suppressed (Lewsey et al, 2010; Whitham, Yang & Goodin, 2006)

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