Salicylic Acid and Systemic Acquired Resistance Play a Role in Attenuating Crown Gall Disease Caused by<i>Agrobacterium tumefaciens</i>

Anand, Ajith; Uppalapati, Srinivasa Rao; Ryu, Choong‐Min; Allen, Stacy N.; Li, Kang; Tang, Yuhong; Mysore, Kirankumar S.

doi:10.1104/pp.107.111302

Cited by 165 publications

(142 citation statements)

References 80 publications

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“…To investigate the role of XRCC4 in Agrobacterium-mediated plant transformation, we used a well-established virus-induced gene silencing (VIGS)-based reverse genetics system (Anand et al, 2007a(Anand et al, , 2007b(Anand et al, , 2008. A partial cDNA of N. benthamiana XRCC4 (see Supplemental Figure 1A online) cloned into the vector pTRV2 was used to silence the XRCC4 gene in N. benthamiana plants.…”

Section: Resultsmentioning

confidence: 99%

Agrobacterium May Delay Plant Nonhomologous End-Joining DNA Repair via XRCC4 to Favor T-DNA Integration

et al. 2012

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Agrobacterium tumefaciens is a soilborne pathogen that causes crown gall disease in many dicotyledonous plants by transfer of a portion of its tumor-inducing plasmid (T-DNA) into the plant genome. Several plant factors that play a role in Agrobacterium attachment to plant cells and transport of T-DNA to the nucleus have been identified, but the T-DNA integration step during transformation is poorly understood and has been proposed to occur via nonhomologous end-joining (NHEJ)-mediated doublestrand DNA break (DSB) repair. Here, we report a negative role of X-RAY CROSS COMPLEMENTATION GROUP4 (XRCC4), one of the key proteins required for NHEJ, in Agrobacterium T-DNA integration. Downregulation of XRCC4 in Arabidopsis and Nicotiana benthamiana increased stable transformation due to increased T-DNA integration. Overexpression of XRCC4 in Arabidopsis decreased stable transformation due to decreased T-DNA integration. Interestingly, XRCC4 directly interacted with Agrobacterium protein VirE2 in a yeast two-hybrid system and in planta. VirE2-expressing Arabidopsis plants were more susceptible to the DNA damaging chemical bleomycin and showed increased stable transformation. We hypothesize that VirE2 titrates or excludes active XRCC4 protein available for DSB repair, thus delaying the closure of DSBs in the chromosome, providing greater opportunity for T-DNA to integrate.

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Section: Resultsmentioning

confidence: 99%

Agrobacterium May Delay Plant Nonhomologous End-Joining DNA Repair via XRCC4 to Favor T-DNA Integration

et al. 2012

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“…The elevated auxin levels at 6 d postinoculation and in tumors may promote agrobacteria invasion by suppression of SA-mediated host defenses. Recently it has been shown that SA has an inhibitory effect on virulence of agrobacteria (Yuan et al, 2007;Anand et al, 2008). SA directly inhibits the expression of the vir regulon of the Ti plasmid that is essential for the transfer and integration of the T-DNA into the host genome.…”

Section: Auxin and Et Are Involved In The Initiation Of Infection Witmentioning

confidence: 99%

“…Levels of SA, however, accumulate to those seen in wild-type plants in response to infection by various pathogens. Previous studies have uncovered a role for SA on Agrobacterium by inhibiting vir gene induction (Yuan et al, 2007, Anand et al, 2008 and thereby affecting agrobacterial virulence. By contrast, defense reactions against many necrotrophic fungi do not involve SA, but rely on ET and JA accumulation and signaling.…”

Section: Introductionmentioning

confidence: 99%

Agrobacterium tumefaciensPromotes Tumor Induction by Modulating Pathogen Defense inArabidopsis thaliana

et al. 2009

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Agrobacterium tumefaciens causes crown gall disease by transferring and integrating bacterial DNA (T-DNA) into the plant genome. To examine the physiological changes and adaptations during Agrobacterium-induced tumor development, we compared the profiles of salicylic acid (SA), ethylene (ET), jasmonic acid (JA), and auxin (indole-3-acetic acid [IAA]) with changes in the Arabidopsis thaliana transcriptome. Our data indicate that host responses were much stronger toward the oncogenic strain C58 than to the disarmed strain GV3101 and that auxin acts as a key modulator of the ArabidopsisAgrobacterium interaction. At initiation of infection, elevated levels of IAA and ET were associated with the induction of host genes involved in IAA, but not ET signaling. After T-DNA integration, SA as well as IAA and ET accumulated, but JA did not. This did not correlate with SA-controlled pathogenesis-related gene expression in the host, although high SA levels in mutant plants prevented tumor development, while low levels promoted it. Our data are consistent with a scenario in which ET and later on SA control virulence of agrobacteria, whereas ET and auxin stimulate neovascularization during tumor formation. We suggest that crosstalk among IAA, ET, and SA balances pathogen defense launched by the host and tumor growth initiated by agrobacteria.

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“…For VIGS, 2-week-old tobacco seedlings were infiltrated with TRV-based VIGS vectors (pTRV2) containing N. benthamiana homologues of the plant defence-related and plant defence hormone signalling genes NbSGT1 and NbICS1 or with the control vector pTRV2::00, as described previously (Anand et al, 2008;Senthil-Kumar and Mysore, 2014;Kim et al, 2016). The Agrobacterium tumefaciens strain GV2260 containing TRV-VIGS vectors was used for VIGS experiments.…”

Section: Virus-induced Gene Silencing (Vigs)mentioning

confidence: 99%

“…BTH, the first commercialized agrochemical to trigger SAR (under the trade names Bion and Actigard in Europe and the USA, respectively), is effective against a broad spectrum of diseases and insect pests, including oomycetes in wheat and tobacco (Nicotiana tabacum), and even insects in tomato (Solanum lycopersicum) (Tally et al, 1999). BTH increases endogenous SA levels and activates SAdependent signalling pathways in plants (Gaffney et al, 1993;Anand et al, 2008;Hammerschmidt, 2009). Reducing SA accumulation in plants through transformation with the SAdegrading gene NahG from the soil bacterium Pseudomonas putida significantly compromises their ability to combat pathogens (Delaney et al, 1994, Molina et al, 1998.…”

Section: Introductionmentioning

confidence: 99%

Root-mediated signal transmission of systemic acquired resistance against above-ground and below-ground pathogens

Song

Sim

Kim

et al. 2016

Ann Bot

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Background and Aims Plants modulate defence signalling networks in response to various biotic stresses via inter-organ communications. The root-mediated transmission of systemic acquired resistance (SAR) against soilborne and air-borne plant pathogens from SAR-induced plants to neighbouring plants subjected to local chemical and pathogen treatments was evaluated.Methods The first two plants out of ten Nicotiana benthamiana seedlings were pre-treated with the SARtriggering chemical benzothiadiazole (BTH). All ten seedlings were then challenged with two pathogenic bacteria, i.e. the root (bacterial wilt) pathogen Ralstonia solanacearum and the leaf (wildfire) pathogen Pseudomonas syringae pv. tabaci, at 7 d after SAR induction.Key Results Disease severity was noticeably lower in BTH-pre-treated plants than in the control. Surprisingly, two plants located next to BTH-treated plants exhibited reduced disease symptoms indicating that SAR signal transmission occurred through the root system. Determinant(s) secreted from the root system were search for and it was found that salicylic acid (SA) is a major molecule involved in SAR transmission through the root. Analysis of the expression of the defence-related genes N. benthamiana pathogenesis-related gene 1a (NbPR1a) and NbPR2 confirmed that BTH treatment elicited SAR via root-root transmission between plants. Plants with knock-down of the multiple resistance component SGT1 and SA biosynthesis-related gene ICS1 by Tobacco rattle virus-mediated virus-induced gene silencing exhibited a lack of root-mediated SAR transmission. The biological relevance of this finding was validated by challenge with the SAR-inducing avirulent pathogen P. syringae pv. syringae instead of BTH, which produced similar results.Conclusions Our findings demonstrated that SAR is transmissible through the root system from SAR-triggered plants to neighbouring plants.

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Salicylic Acid and Systemic Acquired Resistance Play a Role in Attenuating Crown Gall Disease Caused byAgrobacterium tumefaciens

Cited by 165 publications

References 80 publications

Agrobacterium May Delay Plant Nonhomologous End-Joining DNA Repair via XRCC4 to Favor T-DNA Integration

Agrobacterium May Delay Plant Nonhomologous End-Joining DNA Repair via XRCC4 to Favor T-DNA Integration

Agrobacterium tumefaciensPromotes Tumor Induction by Modulating Pathogen Defense inArabidopsis thaliana

Root-mediated signal transmission of systemic acquired resistance against above-ground and below-ground pathogens

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