Diversity, antimicrobial and antioxidant activities of culturable bacterial endophyte communities in Aloe vera.

Twenty-nine culturable bacterial endophytes were isolated from surface-sterilized tissues (root, stem and leaf) of Aloe vera and molecularly characterized to 13 genera: Pseudomonas, Bacillus, Enterobacter, Pantoea, Chryseobacterium, Sphingobacterium, Aeromonas, Providencia, Cedecea, Klebsiella, Cronobacter, Macrococcus and Shigella. The dominant genera include Bacillus (20.7%), Pseudomonas (20.7%) and Enterobacter (13.8%). The crude and ethyl acetate fractions of the metabolites of six isolates, species of Pseudomonas, Bacillus, Chryseobacterium and Shigella, have broad spectral antimicrobial activities against pathogenic Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Salmonella Typhimurium, Proteus vulgaris, Klebsiella pneumoniae, Escherichia coli, Streptococcus pyogenes and Candida albicans, with inhibition zones ranging from 6.0 ± 0.57 to 16.6 ± 0.57 mm. In addition, 80% of the bacterial endophytes produced 1,1-diphenyl-2-picrylhydrazyl (DPPH) with scavenging properties of over 75% when their crude metabolites were compared with ascorbic acid (92%). In conclusion, this study revealed for the first time the endophytic bacteria communities from A. vera (Pseudomonas hibiscicola, Macrococcus caseolyticus, Enterobacter ludwigii, Bacillus anthracis) that produce bioactive compounds with high DPPH scavenging properties (75-88%) and (Bacillus tequilensis, Pseudomonas entomophila, Chryseobacterium indologenes, Bacillus aerophilus) that produce bioactive compounds with antimicrobial activities against bacterial pathogens. Hence, we suggest further investigation and characterization of their bioactive compounds.

Akinsanya MA ，Goh JK ，Lim SP ，Ting AS ... -  《-》

An assessment on the role of endophytic microbes in the therapeutic potential of Fagonia indica.

Rahman L ，Shinwari ZK ，Iqrar I ，Rahman L ，Tanveer F ... -  《Annals of Clinical Microbiology and Antimicrobials》

Growth stage and tissue specific colonization of endophytic bacteria having plant growth promoting traits in hybrid and composite maize (Zea mays L.).

Maize, a crop cultivated worldwide, was investigated for plant tissue and crop stage specific colonization of endophytic bacteria. Such bacterial interactions have high potential to enhance maize grain yield by means of biological nitrogen fixation and/or plant growth promoting activities. In this study endophytic bacteria were isolated from a hybrid PEEHM-5 and composite PC-4 maize varieties using root, stem and leaf tissues of plants at vegetative, flowering and maturity stages of growth. PEEHM-5 harbored higher endophytic bacterial population than PC-4 at all growth stages, with highest in roots and at flowering stage. Morphologically 188 different endophytic isolates (82 from PEEHM-5, 106 from PC-4) were screened for plant growth promoting attributes viz. P, K, Zn solubilization, production of hormones, siderophore, ACC deaminase, HCN, biological nitrogen fixation and biocontrol of two maize fungal pathogens. Thirty one potential PGP isolates on RFLP analysis of their amplified 16S rRNA gene, were clustered in 13 phylogenetic groups. On sequencing and blasting of amplified 16S rRNA gene of representative isolates from each group identified PC-4 endophytic bacterial isolates as Bacillus aryabhattai, Pantoea cypripedii, Bacillus licheniformis, Klebsiella sp., Pantoea dispersa, Klebsiella variicola, Pantoea sp., Agrobacterium larrymoorei and PEEHM-5 endophytic bacterial isolates as Bacillus sp., Bacillus amyloliquefaciens, Lactococcus lactis, Bacillus cereus and Staphylococcus hominis. In planta evaluation of potential isolates at variable chemical fertilizer input indicated their potential in compensating nearly 25% of the fertilizer input as observed on their improvement of shoot and root parameters. Lactococcus lactis inoculation influenced maximum followed by Pantoea and Klebsiella isolates.

Marag PS ，Suman A 《-》

Endophytic bacteria of desert cactus (Euphorbia trigonas Mill) confer drought tolerance and induce growth promotion in tomato (Solanum lycopersicum L.).

Endophytic bacteria isolated from cactus were characterized and assessed for their capability to induce drought tolerance and growth promotion in tomato. A total of 191-bacteria representing 13-genera and 18-species were isolated from wild cactus, Euphorbia trigonas. Bacillus (58), Lysinibacillus (36), Enterobacter (29), Stenotrophomonas (18), Lelliottia (12) and Pseudomonas (12) were the most represented genera. 16S rDNA sequence (>1400-bp) comparison placed the bacterial isolates with Bacillus xiamenensis; Bacillus megaterium; Bacillus cereus; Bacillus amyloliquefaciens; Bacillus velezensis; Brevibacillus brevis; Lysinibacillus fusiformis; Enterobacter cloacae; Lelliottia nimipressuralis; Proteus penneri; Sphingobacterium multivorum; Klebsiella pneumoniae; Pseudomonas putida; Pseudomonas aeruginosa; Stenotrophomonas maltophilia; Citrobacter freundii; Chryseobacterium indologenes and Paracoccus sp. Bacillus xiamenensis was identified for the first time as plant endophyte. Upon bacterization, the endophytes triggered germination and growth promotion in tomato as indicated by 118 % and 52 % more root-biomass under drought-free and drought-induced conditions, respectively. Bacillus amyloliquefaciens CBa_RA37 and B. megaterium RR10 displayed broad spectrum endophytism in tomato. Bacterization of tomato with cactus endophyte showed altered oxidative status, stomatal and photosystem II functioning, internal leaf temperature and relative water content suggestive of physiological de-stressing from moisture stress. Activity of oxidative stress enzymes such as guaiacol peroxidase and catalase was also indicative of endophyte assisted de-stressing of tomato. Re-irrigation on 20-days of drought infliction showed 86.9% recovery of B. amyloliquefaciens CBa_RA37 primed tomato when non-primed plantlets succumbed. The cactus endophytic bacterial strain B. amyloliquefaciens CBa_RA37 showed promise for low-cost, efficient and environmentally friendly bio-inoculant technology to mitigate drought in arid zones of Asian and African continents.

Eke P ，Kumar A ，Sahu KP ，Wakam LN ，Sheoran N ，Ashajyothi M ，Patel A ，Fekam FB ... -  《-》

Antimicrobial activity of endophytic fungi isolated from Dendrobium species in southwestern China.

Cui J ，Wang Y ，Xing Y ，Guo S ，Xiao P ，Wang M ... -  《-》