Salicylic acid-induced changes in physiological parameters and genes of the flavonoid biosynthesis pathway in Artemisia vulgaris and Dendranthema nankingense during aphid feeding

Abstract

ABSTRACT. Phloem-feeding aphids cause serious damage to plants. The mechanisms of plant-aphid interactions are only partially understood and involve multiple pathways, including phytohormones. In order to investigate whether salicylic acid (SA) is involved and how it plays a part in the defense response to the aphid Macrosiphoniella sanbourni, physiological changes and gene expression profiles in response to aphid inoculation with or without SA pretreatment were compared between the aphid-resistant Artemisia vulgaris 'Variegata' and the susceptible chrysanthemum, Dendranthema nankingense. Changes in levels of reactive oxygen species, malondialdehyde (MDA), and flavonoids, and in the expression of genes involved in flavonoid biosynthesis, including PAL (phenylalanine ammonia-lyase), CHS (chalcone synthase), CHI (chalcone isomerase), F3H (flavanone 3-hydroxylase), F3'H (flavanone 3'-hydroxylase), and DFR (dihydroflavonol reductase), were investigated. Levels of hydrogen peroxide, superoxide anions, MDA, and flavonoids, and their related gene expression, increased after aphid infestation and SA pretreatment followed by aphid infestation; the aphid-resistant A. vulgaris exhibited a more rapid response than the aphid-susceptible D. nankingense to SA treatment and aphid infestation. Taken together, our results suggest that SA could be used to increase aphid resistance in the chrysanthemum.

Flavanone-3-Hydroxylase Plays an Important Role in the Biosynthesis of Spruce Phenolic Defenses Against Bark Beetles and Their Fungal Associates

“…We also elucidated an unknown step in the Norway spruce flavonoid pathway for the biosynthesis of these compounds by characterizing a novel F3H enzyme. In plants, high F3H gene expression is not only known to increase resistance against biotrophic and necotrophic attackers (Mahajan and Yadav, 2014; Sun et al, 2016), but is also involved in increasing tolerance to cold, drought and heat stress (Mahajan and Yadav, 2014; Meng et al, 2015; Song et al, 2016). Selecting conifer genotypes with high F3H gene expression might therefore partially counteract the detrimental effects of climate change, as these genotypes might not only be more resistant to bark beetle attack, but also more resistant to abiotic stress which is the indirect trigger of large bark beetle outbreaks.…”

“…Flavanone-3-hydroxylase gene expression is positively regulated by the plant hormones salicylic acid (Sun et al, 2016), jasmonic acid (Meng et al, 2015), and abscisic acid (Song et al, 2016). Increased transcription of the F3H gene leads to tolerance to abiotic as well as biotic stress, including drought (Watkinson et al, 2006), saline conditions (Mahajan and Yadav, 2014), cold (Meng et al, 2015), UV radiation (Liu et al, 2013) as well as biotrophic and necrotrophic attackers (Sun et al, 2016).…”

“…Flavanone-3-hydroxylase gene expression is positively regulated by the plant hormones salicylic acid (Sun et al, 2016), jasmonic acid (Meng et al, 2015), and abscisic acid (Song et al, 2016). Increased transcription of the F3H gene leads to tolerance to abiotic as well as biotic stress, including drought (Watkinson et al, 2006), saline conditions (Mahajan and Yadav, 2014), cold (Meng et al, 2015), UV radiation (Liu et al, 2013) as well as biotrophic and necrotrophic attackers (Sun et al, 2016). High expression of this enzyme results in accumulation of proanthocyanidins (PAs), which are major end products of the pathway (Beritognolo et al, 2002; Song et al, 2016), higher levels of antioxidants (Meng et al, 2015) and lower levels of reactive oxygen species (Mahajan and Yadav, 2014).…”

The OsmiR396–OsGRF8–OsF3H‐flavonoid pathway mediates resistance to the brown planthopper in rice (Oryza sativa)

“…In this study, anthocyanin content was measured for Arabidopsis plants as previously described (Gou et al ., ) and flavonoid content was measured for rice plants accordingly to Sun et al . with modification (Sun et al ., ). 1 g powder milled from fresh leaves was taken for extraction with 10 mL 50% ethanol for 1 h and repeated 2–3 times, and made up to 50 mL.…”

Studies on Inducer Mediated Resistance Responses against Biological Fitness of Brevicoryne brassicae (Homoptera: Aphididae) on Brassica napus

“…Work on other plants like wheat, barley, soybean, and Brassica spp., has shown the effectiveness of inducedresistance against bio-fitness attributes of Myzus persicae and Lipaphis spp. aphids (Chaman et al 2003;Studham and MacIntosh 2013;Mahmoud and Osman 2015;Sun et al 2016;Nouri-Ganbalani et al 2018). Its underlying mechanism involves the activation of defense transcriptional machinery, against aphid infestations (Studham and MacIntosh 2013).…”