Endophytes from maize with plant growth promotion and biocontrol activity under drought stress

Vardharajula, Sandhya; Shrivastava, Manjari; Ali, Sk. Z.; Prasad, V.S.S.

doi:10.3103/s1068367417010165

Cited by 97 publications

(42 citation statements)

References 63 publications

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“…Using 454 next generation sequencing we assessed the composition and abundance of endophytic communities inside roots of amilaceous maize plants grown under fallow and maize-cultivated conditions in Andean chacras. Pyrosequencing revealed an unprecedented number of bacterial endophytes as compared with those of the genera found in previous studies based on culture-dependent and culture-independent methods (McInroy and Kloepper, 1995 ; Chelius and Triplett, 2001 ; Rai et al, 2007 ; Pereira et al, 2011 ; Ikeda et al, 2013 ; Sandhya et al, 2017 ). Altogether, a 15.26% of the total sequences found inside roots corresponded to unclassified bacteria, which indicates the presence of hitherto uncultured bacterial groups.…”

Section: Discussionsupporting

confidence: 46%

“…The presence of Streptococcus, Dyella and Staphylococcus is intriguing as they are well-known human pathogens; these three genera have been detected in maize seeds, roots of blackberry, grapevine shoots, apple and orange fresh fruits (Liu et al, 2013 ; Phukon et al, 2013 ; Pinto et al, 2014 ; Yousaf et al, 2014 ; Contreras et al, 2016 ) and they were reported as the dominant endophytes of legumes (Boine et al, 2008 ; Becerra-Castro et al, 2011 ). Moreover, recent works suggest that pathogenic bacteria are common inhabitants of the interior of plants (Szilagyi-Zecchin et al, 2014 ; Blain et al, 2017 ; Sandhya et al, 2017 ).…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies have analyzed bacterial taxa associated with maize. Most of the work has been done by using culture-dependent methods (Rai et al, 2007 ; Rijavec et al, 2007 ; Pereira et al, 2009 , 2011 ; Ikeda et al, 2013 ; Celador-Lera et al, 2016 ; Menéndez et al, 2016 ; Sandhya et al, 2017 ) or assessed bacterial diversity independently of culture approaches (Schmalenberger and Tebbe, 2003 ; Herschkovitz et al, 2005a , b ; Pereira et al, 2011 ; Correa-Galeote et al, 2016 ; Liu et al, 2017 ). The high-throughput pyrosequencing technology introduced by 454 Life Science (Margulies et al, 2005 ; Rothberg and Leamon, 2008 ) has been used to assess diversity in cultivar-specific bacterial endophyte communities in potato roots (Manter et al, 2010 ), leaf vegetables (Jackson et al, 2013 ), the spermosphere and phyllosphere of spinach (López-Velasco et al, 2013 ), tomato leaves (Romero et al, 2014 ), grapevine leaves and stems (Yousaf et al, 2014 ) and roots and shoots of cucumber (Eevers et al, 2016 ).…”

Section: Introductionmentioning

confidence: 99%

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Maize Endophytic Bacterial Diversity as Affected by Soil Cultivation History

2018

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The bacterial endophytic communities residing within roots of maize (Zea mays L.) plants cultivated by a sustainable management in soils from the Quechua maize belt (Peruvian Andes) were examined using tags pyrosequencing spanning the V4 and V5 hypervariable regions of the 16S rRNA. Across four replicate libraries, two corresponding to sequences of endophytic bacteria from long time maize-cultivated soils and the other two obtained from fallow soils, 793 bacterial sequences were found that grouped into 188 bacterial operational taxonomic units (OTUs, 97% genetic similarity). The numbers of OTUs in the libraries from the maize-cultivated soils were significantly higher than those found in the libraries from fallow soils. A mean of 30 genera were found in the fallow soil libraries and 47 were in those from the maize-cultivated soils. Both alpha and beta diversity indexes showed clear differences between bacterial endophytic populations from plants with different soil cultivation history and that the soils cultivated for long time requires a higher diversity of endophytes. The number of sequences corresponding to main genera Sphingomonas, Herbaspirillum, Bradyrhizobium and Methylophilus in the maize-cultivated libraries were statistically more abundant than those from the fallow soils. Sequences of genera Dyella and Sreptococcus were significantly more abundant in the libraries from the fallow soils. Relative abundance of genera Burkholderia, candidatus Glomeribacter, Staphylococcus, Variovorax, Bacillus and Chitinophaga were similar among libraries. A canonical correspondence analysis of the relative abundance of the main genera showed that the four libraries distributed in two clearly separated groups. Our results suggest that cultivation history is an important driver of endophytic colonization of maize and that after a long time of cultivation of the soil the maize plants need to increase the richness of the bacterial endophytes communities.

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Section: Discussionsupporting

confidence: 46%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Maize Endophytic Bacterial Diversity as Affected by Soil Cultivation History

2018

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“…Another recent study ( Sandhya et al, 2017 ) showed the potential of seed endophytes as biocontrol agents. In that study, maize seeds and roots were used as sources of bacterial endophytes; 10 out of 39 endophytic bacteria demonstrated diverse in vitro activities comprising growth promotion and antagonism against 6 fungal phytopathogens ( Macrophomina phaseolina , Rhizoctonia solani , Fusarium oxysporum , Sclerotium rolfsii , Pythium aphanidermatum and Alternaria sp.)…”

Section: Discussionmentioning

confidence: 99%

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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“…Production of phytohormones is a key attribute enabling endophytes to promote plant growth by improving the ability of the host to tolerate and overcome different abiotic and biotic environmental stresses (Ma et al 2016;Hamayun et al 2017;Khan et al 2017;Sandhya et al 2017). Therefore, to determine the phytohormones i.e.…”

Section: Discussionmentioning

confidence: 99%

Aspergillus niger CSR3 regulates plant endogenous hormones and secondary metabolites by producing gibberellins and indoleacetic acid

Lubna

Asaf

Hamayun

et al. 2018

Journal of Plant Interactions

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In this study, an endophytic fungus, Aspergillus niger CSR3, was isolated from Cannabis sativa. The culture filtrate (CF) was initially screened for growth-promoting activities such as the presence of siderophores, phosphate solubilization, and the production of indole acetic acid (IAA) and gibberellins and was further assayed for its ability to promote the growth of mutant waito-C rice. Nearly all plant growth attributes examined (root-shoot length, biomass, and chlorophyll content) were significantly enhanced by treatment with CSR3. This growth promotion action was due to the presence of various types of gibberellins (GAs) and IAA in the endophyte CF. Moreover, the presence of GA pathway genes (P50-1, P450-3, P450-4, ggs2, and des) was confirmed by means of semi-quantitative RT-PCR. Finally, the application of CSR3 spore suspension with uniconazole and yucasin on maize seedlings revealed that, similar to exogenous IAA and GA 3 , CSR3 has the potential to alleviate the inhibitory effect of these inhibitors.

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Endophytes from maize with plant growth promotion and biocontrol activity under drought stress

Cited by 97 publications

References 63 publications

Maize Endophytic Bacterial Diversity as Affected by Soil Cultivation History

Maize Endophytic Bacterial Diversity as Affected by Soil Cultivation History

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

Aspergillus niger CSR3 regulates plant endogenous hormones and secondary metabolites by producing gibberellins and indoleacetic acid

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