Diversity of bacteria and archaea in the rhizosphere of bioenergy crop Jatropha curcas

Abstract

Plant-microbial interaction in rhizosphere plays vital role in shaping plant’s growth and ecosystem function. Most of the rhizospheric microbial diversity studies are restricted to bacteria. In natural ecosystem, archaea also constitutes a major component of the microbial population. However, their diversity is less known compared to bacteria. Experiments were carried out to examine diversity of bacteria and archaea in the rhizosphere of bioenergy crop Jatropha curcas (J. curcas). Samples were collected from three locations varying widely in the soil physico-chemical properties. Diversity was estimated by terminal restriction fragment length polymorphism (TRFLP) targeting 16S rRNA gene of bacteria and archaea. Fifteen bacterial and 17 archaeal terminal restriction fragments (TRFs) were retrieved from J. curcas rhizosphere. Bacterial indicative TRFs were Actinobacteria, Firmicutes, Acidobacteria, Verrumicrobiaceae, and Chlroflexi. Major archaeal TRFs were crenarchaeota, and euryarchaeota. In case of bacteria, relative fluorescence was low for TRF160 and high for TRF51, TRF 420. Similarly, for archaea relative fluorescence of TRF 218, and TRF 282 was low and high for TRF 278, TRF468 and TRF93. Principal component analysis (PCA) of bacterial TRFs designated PC 1 with 46.83% of variation and PC2 with 31.07% variation. Archaeal TRFs designated 90.94% of variation by PC1 and 9.05% by PC2. Simpson index varied from 0.530 to 0.880 and Shannon index from 1.462 to 3.139 for bacteria. For archaea, Simpson index varied from 0.855 to 0.897 and Shannon index varied from 3.027 to 3.155. Study concluded that rhizosphere of J. curcas constituted of diverse set of both bacteria and archaea, which might have promising plant growth promoting activities.

Screening and Biocontrol Potential of Rhizobacteria Native to Gangetic Plains and Hilly Regions to Induce Systemic Resistance and Promote Plant Growth in Chilli against Bacterial Wilt Disease

“…Microbial diversity was highest in the Middle Gangetic Plain region as compared with another geographical region. Similar results have been observed with microbial diversity of rhizospheric Jatropha crop, which showed to be highest in Noida and Bhopal regions rather than Jabalpur in India [ 79 ]. Similar results were observed in Ranunculus glacialis rhizospheric microbial diversity [ 80 ].…”

In Vitro Characterization of Endophytic Bacteria Associated With Physic Nut (Jatropha Curcas L.) and Their Potential for Plant-Growth Promotion and Biocontrol / Caracterização in Vitro De Bactérias Endofíticas Associadas Ao Pinhão-Manso (Jatropha Curcas L.) E Seu Potencial De Promoção De Crescimento Vegetal E Biocontrole

“…Although endophytes are prevalent, the literature about this group of microorganisms from renewable energy plants J. curcas is scarce. Some studies of the endophytic and rhizospheric bacteria diversity associated with J. curcas found the phyla Actinobacteria, Acidobacteria, Chlroflexi, Firmicutes, and Verrucomicrobia Annapurna;Saraf, 2012;Dubey et al 2016;Madhaiyan et al, 2012;Qin et al, 2015); which demonstrates the ability of the phyla found in the present study in Annapurna;Saraf, 2012;Madhaiyan et al, 2012;Madhaiyan et al, 2013). These genera have already been described as capable of promoting plant growth in various other crops (Chauhan, Bagyaraj, Sharma, 2013;Castro et al, 2017;Batista et al, 2018).…”

Archaea, tiny helpers of land plants

“… Archaea Discovery location Potential function Reference Crenarchaeota Mycorrhizospheres scots pine [10] Rhizosphere of macrophyte Littorella uniflora Ammonia oxidation [24] Marine or wetland Sulfur reduction ( dissimilatory sulfite reductases ) [37] Sulfolobus acidocaldarius Indole acetic acid production [41] Rhizosphere of Jatropha curcas Nitrification [48] Thermoproteaceae, Sulfolobaceae Desulfurococcaceae Bacteriosin or terpene in genome [50] Euryarchaeota Methanogens , Rice cluster Ⅰ Rice fields Methane-oxidizing archaea [3] , [32] , [59] Marine or wetland Sulfur reduction ( dissimilatory sulfite reductases ) [37] Forest and grassland soil Phosphatase enzymes phoD and phoX [26] Halobacteria Rhizophora mangle Phosphorous solubilization [27] , [28] Halobactierum Halococcus Halonemum strobilaceum (Chenopodiaceae) Phosphorous Solubilization [27] , [29] Halolamina Rhizosphere of grasses in hypersaline soil Phosphorous solubilization [27] , [30] Methanomicrobia, Halobacteriaceae Rhizosphere of Bog vagetation CO2 fixation, oxidative stress …”

“…Plants can also grow in environments with high levels of abiotic stress. Metagenomic analysis of the rhizosphere of Jatropha curcas, which adapted to grow under salt stress and high temperature conditions, showed high abundances of Crenarchaeota and Euryarchaeota [48] ( Table 1 ). Although the detailed reason is not known, Crenarchaeota and Euryarchaeota may help the Jatropha curcas adapt to salt stress and high temperature condition.…”