Expression Profiling of Four Defense-Related Buffalograss Transcripts in Response to Chinch Bug (Hemiptera: Blissidae) Feeding

Abstract

Oxidative enzymes are one of many key players in plant tolerance responses and defense signaling pathways. This study evaluated gene expression of four buffalograss transcripts (two peroxidases, a catalase, and a GRAS (gibberellic acid insensitive [GAI], repressor of GAI, and scarecrow) and total peroxidase activity in response to western chinch bug (Blissus occiduus Barber) feeding in susceptible and resistant buffalograsses (Buchloë dactyloides (Nuttall) Engelmann). Basal levels of all four transcripts were consistently higher in the resistant buffalograss when compared with the susceptible genotype, which suggests important physiological differences exist between the two buffalograsses. The four defense-related transcripts also showed differential expression between infested and control plants for both the resistant and susceptible buffalograsses. Differences in total peroxidase activity were also detected between control and infested plants, and basal peroxidase activity was higher in the resistant genotype. Overall, this study indicates that elevated basal levels of specific peroxidases, catalases, and GRAS may be an effective buffalograss defense strategy against chinch bug feeding and other similar biotic stresses.

Transcriptional responses of tolerant and susceptible soybeans to soybean aphid (Aphis glycines Matsumura) herbivory

“…In contrast, peroxidase genes were not differentially expressed in the susceptible plants at either day 5 or 15 after aphid infestation. These data are consistent with a previously proposed hypothesis (Heng-Moss et al 2004;Franzen et al 2007;Gutsche et al 2009;Ramm et al 2013) that tolerant plants have the ability to elevate their level of reactive oxygen species (ROS)-scavenging enzymes, such as peroxidases, which enable them to efficiently remove intracellular ROS that accumulate in response to aphid feeding.…”

“…The large differences in the DEGs suggest that tolerance could have some basis in elevated expression of stressameliorating proteins, such as peroxidases and cytochrome P450s and plausibly in stress-sensing proteins such as the WRKYs and LRR. Similar results have been reported in other studies (Ramm et al 2013;Studham and Macintosh 2013). GO analysis did not result in data enrichment.…”

Transcriptional Profiling of Resistant and Susceptible Buffalograsses in Response to Blissus occiduus (Hemiptera: Blissidae) Feeding

“…High basal read counts of select peroxidase transcripts in the Prestige transcriptome demonstrate that these two buffalograsses are physiologically very different with respect to the types and relative levels of oxidative enzymes. These data support the idea that Prestige is better prepared to deal with oxidative stresses associated with insect herbivory, and are consistent with previous research documenting significantly higher basal expression levels of specific defense-related transcripts such as peroxidase in Prestige control plants compared with 378 control plants (Ramm et al 2013). Overall, these results indicate that elevated basal expression levels of peroxidases could be one facet of the mechanisms underlying tolerance to chinch bug feeding in Prestige as compared with the susceptible 378 genotype.…”

“…Comparison of data from control and chinch bug-infested plants, and subsequent comparison of tolerant and susceptible genotypes, allowed for the identification of DE genes between control plants of the two genotypes and expression level changes in both the tolerant and susceptible buffalograsses in response to chinch bug feeding. Many of the changes documented in this study support those found in other studies investigating tolerant Prestige and susceptible 378 buffalograsses , Gulsen 2010, Ramm et al 2013). In total, seven peroxidases had higher expression in Prestige control plants than 378 control plants (Table 3).…”

“…Furthermore, the upregulation and downregulation patterns of these peroxidases suggest that ROS accumulation and detoxification occurs simultaneously in response to chinch bug feeding (Park et al 2005, Gutsche et al 2009b. ROS may play multiple roles in the tolerant response of Prestige to chinch bug feeding (Ramm et al 2013). Increased levels of ROS may act as a signaling molecule for increased activation of ROS-dependent genes, defense-related transcripts, and ROS scavengers such as peroxidases and catalases as has been reported in other studies (Passardi et al 2005, Miller et al 2009, Torres 2010.…”