Transgenic expression of antifungal pathogenesis-related proteins against phytopathogenic fungi – 15 years of success

Moosa, Anam; Farzand, Ayaz; Sahi, Shahbaz Talib; Khan, Sajid Aleem

doi:10.1080/07929978.2017.1288407

Cited by 31 publications

(23 citation statements)

References 166 publications

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“…Noteworthy, the antifungal activity of some pathogenesis-related (PR) proteins secreted by host plants has been associated with their ribonuclease activity, including the PR-4 and PR-10 families ( Filipenko et al, 2013 ; Miranda et al, 2017 ; Moosa et al, 2017 ). The associated mechanism(s) of action of these ribonucleases is not clear but may include direct antagonism (by penetrating fungal cells and degrading native mRNA) or indirect antagonism (by inducing host programmed cell death) ( Filipenko et al, 2013 ; Miranda et al, 2017 ; Moosa et al, 2017 ). Further experiments will be required to determine whether the extracellular RNase activity of any of the endophytes plays a role in their phytopathogen suppression, and if so, their mechanism of action.…”

Section: Discussionmentioning

confidence: 99%

“…These VOCs, including acetoin and diacetyl, exert their signaling functions by stimulating the transcription of plant host genes employed in metabolic, physiological and defensive activities ( Asari et al, 2016 ). As part of their cascade of defense responses, plants can secrete pathogenesis related proteins (PR proteins), including those with ribonuclease (RNase) activity, that can directly antagonize fungal phytopathogens by penetrating fungal cells or by inducing programmed cell death of plant cells under attack ( Filipenko et al, 2013 ; Miranda et al, 2017 ; Moosa et al, 2017 ), though whether endophytes supplement this host activity is not clear.…”

Section: Introductionmentioning

confidence: 99%

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Bacterial Seed Endophytes of Domesticated Cucurbits Antagonize Fungal and Oomycete Pathogens Including Powdery Mildew

2018

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The cucurbit vegetables, including cucumbers, melons and pumpkins, have been cultivated for thousands of years without fungicides. However, their seed germination stage is prone to be infected by soil-borne fungal and oomycete pathogens. Endophytes are symbionts that reside inside plant tissues including seeds. Seed endophytes are founders of the juvenile plant microbiome and can promote host defense at seed germination and later stages. We previously isolated 169 bacterial endophytes associated with seeds of diverse cultivated cucurbits. We hypothesized that these endophytes can antagonize major fungal and oomycete pathogens. Here we tested the endophytes for in vitro antagonism (dual culture assays) against important soil-borne pathogens (Rhizoctonia solani, Fusarium graminearum, Phytophthora capsici, Pythium aphanidermatum). The endophytes were also assayed in planta (leaf disk and detached leaf bioassays) for antagonism against a foliar pathogen of global importance, Podosphaera fuliginea, the causative agent of cucurbit powdery mildew. The endophytes were further tested in vitro for secretion of volatile organic compounds (VOCs) known to induce plant defense. Extracellular ribonuclease activity was also tested, as a subset of pathogenesis-related (PR) proteins of plant hosts implicated in suppression of fungal pathogens, displays ribonuclease activity. An unexpected majority of the endophytes (70%, 118/169) exhibited antagonism to the five phytopathogens, of which 68% (50/73) of in vitro antagonists belong to the genera Bacillus and Paenibacillus. All Lactococcus and Pantoea endophytes exhibited anti-oomycete activity. However, amongst the most effective inoculants against Podosphaera fuliginea were Pediococcus and Pantoea endophytes. Interestingly, 67% (113/169) of endophytes emitted host defense inducing VOCs (acetoin/diacetyl) and 62% (104/169) secreted extracellular ribonucleases in vitro, respectively. These results show that seeds of cultivated cucurbits package microbes with significant disease-suppression potential. As seeds can act as vectors for genetic transmission of endophytes across host generations, it is interesting to hypothesize whether humans, when selecting seeds of healthy hosts, may have inadvertently selected for disease-suppressing seed endophytes. As the majority of pathogen-suppressing endophytes belong to Bacillus and Paenibacillus, and since Bacilli are widely used as commercial biocontrol agents of vegetables, we propose that these agents are mimicking the ecological niche established by their endophytic cousins.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bacterial Seed Endophytes of Domesticated Cucurbits Antagonize Fungal and Oomycete Pathogens Including Powdery Mildew

2018

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“…ISR is a systemic resistance response induced by rhizobacteria that can suppress pathogens and ultimately diseases in plants [16]. ISR induction triggers the production of plant defense-related proteins such as peroxidase (POD), lipoxygenase (LOX), chitinase (CHI), and β-1,3-glucanase (GLU) [17,18], and enzymatic antioxidants such as superoxide dismutase (SOD), phenylalanine lyase (PAL), and polyphenol oxidase (PPO) involved in plant defense [19,20,21]. Purified fengycin and surfactin can induce ISR in plants, as is evident from previous studies [22].…”

Section: Introductionmentioning

confidence: 99%

Suppression of Sclerotinia sclerotiorum by the Induction of Systemic Resistance and Regulation of Antioxidant Pathways in Tomato Using Fengycin Produced by Bacillus amyloliquefaciens FZB42

et al. 2019

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Lipopeptides from Bacillus species exhibit promising biological control activity against plant pathogens. This study aimed to explore the potential of purified fengycin to induce systemic resistance in tomato against Sclerotinia sclerotiorum. Bacillus amyloliquefaciens FZB42, its mutant AK1S, and their corresponding metabolites showed in vitro inhibition of S. sclerotiorum mycelium. Fengycin derived from an AK1S mutant was purified and identified through HPLC and MALDI-TOF-MS, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed structural deformities in the fungal mycelium. Moreover, fengycin induced the accumulation of reactive oxygen species (ROS) in S. sclerotiorum mycelium and downregulated the expression of ROS-scavenging genes viz., superoxide dismutase (SsSOD1), peroxidase (SsPO), and catalase (SsCAT1) compared to the untreated control. Furthermore, the lesion size was dramatically reduced in fengycin-treated tomato plants compared to plants infected with S. sclerotiorum only in a greenhouse experiment. Additionally, the transcriptional regulation of defense-related genes GST, SOD, PAL, HMGR, and MPK3 showed the highest upsurge in expression at 48 h post-inoculation (hpi). However, their expression was subsequently decreased at 96 hpi in fengycin + S. sclerotiorum treatment compared to the plants treated with fengycin only. Conversely, the expression of PPO increased in a linear manner up to 96 hpi.

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“…Regarding the role of wheat and rice PRs proteins in defense system, PR-2, PR-5, and PR-10 proteins can directly affect pathogen integrity or release signal molecules through their enzymatic activity that act as elicitors to induce plant defense related pathways [ 22 , 23 , 24 ]. Endochitinases ( PR-4 ) and thaumatin like proteins ( PR-5 ) of wheat, maize, barley, sorghum, and oat are implicated in defense responses against a diverse group of pathogens, including fungal and oomycete pathogens with different lifestyle [ 22 , 24 , 58 , 59 ]. Similarly, MYB transcription factors ( TaLHY ) plays key roles in defense mechanism of the plants [ 30 , 60 ].…”

Section: Discussionmentioning

confidence: 99%

Wheat Varietal Response to Tilletia controversa J. G. Kühn Using qRT-PCR and Laser Confocal Microscopy

Chen

Muhae-Ud-Din

Liu

et al. 2021

Genes

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Tilletia controversa J. G. Kühn is a causal organism of dwarf bunt in wheat. Understanding the interaction of wheat and T. controversa is of practical and scientific importance for disease control. In this study, the relative expression of TaLHY and TaPR-4 and TaPR-5 genes was higher in a resistant (Yinong 18) and moderately resistant (Pin 9928) cultivars rather than susceptible (Dongxuan 3) cultivar at 72 h post inoculation (hpi) with T. controversa. Similarly, the expression of defensin, TaPR-2 and TaPR-10 genes was observed higher in resistant and moderately resistant cultivars after exogenous application of phytohormones, including methyl jasmonate, salicylic acid, and abscisic acid. Laser confocal microscopy was used to track the fungal hyphae in the roots, leaves, and tapetum cells, which of susceptible cultivar were infected harshly by T. controversa than moderately resistant and resistant cultivars. There were no fungal hyphae in tapetum cells in susceptible cultivar after methyl jasmonate, salicylic acid and abscisic acid treatments. Moreover, after T. controversa infection, the pollen germination was of 80.06, 58.73, and 0.67% in resistant, moderately resistant and susceptible cultivars, respectively. The above results suggested that the use using of resistant cultivar is a good option against the dwarf bunt disease.

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Transgenic expression of antifungal pathogenesis-related proteins against phytopathogenic fungi – 15 years of success

Cited by 31 publications

References 166 publications

Bacterial Seed Endophytes of Domesticated Cucurbits Antagonize Fungal and Oomycete Pathogens Including Powdery Mildew

Bacterial Seed Endophytes of Domesticated Cucurbits Antagonize Fungal and Oomycete Pathogens Including Powdery Mildew

Suppression of Sclerotinia sclerotiorum by the Induction of Systemic Resistance and Regulation of Antioxidant Pathways in Tomato Using Fengycin Produced by Bacillus amyloliquefaciens FZB42

Wheat Varietal Response to Tilletia controversa J. G. Kühn Using qRT-PCR and Laser Confocal Microscopy

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