Systemic Acquired Resistance Induced by Agrobacterium tumefaciens in Peach and Differential Expression of PR1 Genes

Abstract

<jats:p>Crown gall disease caused by <jats:italic>Agrobacterium tumefaciens</jats:italic> affects a wide range of horticultural plants, and has no effective treatment. During the evaluation of crown gall resistance of peach germplasm resources, we observed enhanced resistance to subsequent invasion that was activated by virulence of <jats:italic>A. tumefaciens</jats:italic> in two peach cultivars. To further verify the phenotype observed in field experiments, systemic acquired resistance (SAR)-related salicylic acid (SA) and <jats:italic>PR1</jats:italic> genes were investigated. The levels of SA were elevated in two cultivars, and these high levels were maintained for 35 days postinoculation. Compared with mock-inoculated controls, eight of the 22 candidate <jats:italic>PpPR1</jats:italic> genes in <jats:italic>A. tumefaciens</jats:italic>-inoculated samples were significantly upregulated and three were downregulated in response to inoculation with <jats:italic>A. tumefaciens</jats:italic>. These data suggested that SA-induced SAR was activated in two peach cultivars by virulent <jats:italic>A. tumefaciens</jats:italic> infection. In addition, the eight induced <jats:italic>PpPR1</jats:italic> genes can be used as molecular markers in defense studies in peach.</jats:p>

Insight into the Bacterial Endophytic Communities of Peach Cultivars Related to Crown Gall Disease Resistance

“…The efficient inhibition of A. tumefaciens by "protective" endophytes might maintain the pathogen population below the threshold required for quorum sensing, restrict the T-DNA transfer from A. tumefaciens to peach, and cause smaller galls (60). Furthermore, it has been reported that salicylic acid (SA)-induced systemic acquired resistance is activated in "Honggengansutao" by pathogen infection (9).…”

“…A total of 180 peach plants were grown in the greenhouse experiment (90 per cultivar), including 45 plants of each cultivar inoculated with A. tumefaciens on root collars (I) and 45 mock-inoculated plants used as controls (M). The pathogen inoculation was performed as described by Hao et al (9). Cuts of 1 cm in length were made into the cambium at the root collar, and 20 l of either bacterial inoculum (10 9 CFU/ml) or sterile deionized water was applied to the incision, which was then covered by autoclaved vermiculite.…”

Silencing of Agrobacterium tumefaciens oncogenes ipt and iaaM induces resistance to crown gall disease in plum but not in apricot

“…Although no genes for resistance to crown gall have been described, differences in tolerance against A. tumefaciens have been observed in different Prunus species . In a recent work, Hao et al . observed two peach cultivars with enhanced resistance to A. tumefaciens .…”

Effects of cobalt ions and cobalt nanoparticles on transient expression of gus gene in catharanthus roseus suspension cultures

“…Bacterial cells provoked expression of plant defense genes including PAL, POD, and CrPR1a genes with a lag period of 12-24 h. In agreement with these results, Ditt et al (2001) observed differential expression of defense genes in Ageratum conyzoides cell culture bout 24 h post-infection with A tumefaciens. A longer lag period of 3 days was observed by Hao et al (2015) for PR-1 genes in peach plants. The same lag period was recorded for PR-10 and POD genes in grape embryonic callus (F. Zhao et al, 2011).…”