Barley yellow dwarf virus Infection Leads to Higher Chemical Defense Signals and Lower Electrophysiological Reactions in Susceptible Compared to Tolerant Barley Genotypes

Abstract

Barley yellow dwarf virus (BYDV) is a phloem limited virus that is persistently transmitted by aphids. Due to huge yield losses in agriculture, the virus is of high economic relevance. Since the control of the virus itself is not possible, tolerant barley genotypes are considered as the most effective approach to avoid yield losses. Although several genes and quantitative trait loci are known and used in barley breeding for virus tolerance, little is known about molecular and physiological backgrounds of this trait. Therefore, we compared the anatomy and early defense responses of a virus susceptible to those of a virus-tolerant cultivar. One of the very early defense responses is the transmission of electrophysiological reactions. Electrophysiological reactions to BYDV infection might differ between susceptible and tolerant cultivars, since BYDV causes disintegration of sieve elements in susceptible cultivars. The structure of vascular bundles, xylem vessels and sieve elements was examined using microscopy. All three were significantly decreased in size in infected susceptible plants where the virus causes disintegration of sieve elements. This could be associated with an uncontrolled ion exchange between the sieve-element lumen and apoplast. Further, a reduced electrophysiological isolation would negatively affect the propagation of electrophysiological reactions. To test the influence of BYDV infection on electrophysiological reactions, electropotential waves (EPWs) induced by leaf-tip burning were recorded using aphids as bioelectrodes. EPWs in infected susceptible plants disappeared already after 10 cm in contrast to those in healthy susceptible or infected tolerant or healthy tolerant plants. Another early plant defense reaction is an increase in reactive oxygen species (ROS). Using a fluorescent dye, we found a significant increase in ROS content in infected susceptible plants but not in infected tolerant plants. Similar results were found for the phytohormones abscisic acid and three jasmonates. Salicylic acid levels were generally higher after BYDV infection compared to uninfected plants. Heat stimulation caused an increase in jasmonates. By shedding light on the plant defense mechanisms against BYDV, this study, provides further knowledge for breeding virus tolerant plants.

Jasmonic acid regulation of the anti‐herbivory mechanism conferred by fungal endophytes in grasses

“…Lastly, the separation differences between all compounds were optimized in MRM, achieving a detection limit of 5 nmol with excellent chromatographic peak shape and signal to noise ratio. Similar protocols have been used to quantify plant hormones, and these studies report hormone concentrations comparable to those reported here (Bastías et al., ,; Davis, Bosque‐Pérez, Popova, & Eigenbrode, ; Eberl, Hammerbacher, Gershenzon, & Unsicker, ; Ohnmeiss & Baldwin, ; Paulmann et al., ).…”

A Genome-Wide View of Transcriptional Responses during Aphis glycines Infestation in Soybean

“…However, in our study, although genes related to superoxide metabolism was enriched in GO terms, no significant changes in ROS synthesis were observed in both antixenotic and antibiotic soybean during aphid infestation, but they were increased significantly in the susceptible genotype ( Figure 7). Similar results were reported in barley infected by barley yellow dwarf virus (BYDV) [53] and tolerant soybean during a short-term aphid infestation [50]. This suggested that ROS was not involved in the response to aphid attack in resistant soybean with limited infestation period.…”

Abscisic Acid—Enemy or Savior in the Response of Cereals to Abiotic and Biotic Stresses?

“…ABA content was found to increase consistently over the course of the observation period (from 8, through 16 and 24, to 32 dpi) in wheat leaves infected with BYDV. Furthermore, Paulmann et al [ 203 ] demonstrated the increase in ABA content in leaves of a BYDV-susceptible cultivar of H . vulgare inoculated with BYDV at 6 weeks post-infection in comparison to the noninoculated ones.…”