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Microbiological Research Nov 2019Endophytic bacteria isolated from cactus were characterized and assessed for their capability to induce drought tolerance and growth promotion in tomato. A total of...
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.
Topics: Acclimatization; Bacillus; Biomass; Cactaceae; Cameroon; DNA, Ribosomal; Desert Climate; Droughts; Endophytes; Solanum lycopersicum; Phylogeny; Plant Development; Plant Leaves; Plant Roots; RNA, Ribosomal, 16S; Rifamycins; Sequence Analysis; Soil Microbiology; Stress, Physiological
PubMed: 31442862
DOI: 10.1016/j.micres.2019.126302 -
Nature Communications Jun 2020Bacteria have evolved sophisticated adaptive immune systems, called CRISPR-Cas, that provide sequence-specific protection against phage infection. In turn, phages have...
Bacteria have evolved sophisticated adaptive immune systems, called CRISPR-Cas, that provide sequence-specific protection against phage infection. In turn, phages have evolved a broad spectrum of anti-CRISPRs that suppress these immune systems. Here we report structures of anti-CRISPR protein IF9 (AcrIF9) in complex with the type I-F CRISPR RNA-guided surveillance complex (Csy). In addition to sterically blocking the hybridization of complementary dsDNA to the CRISPR RNA, our results show that AcrIF9 binding also promotes non-sequence-specific engagement with dsDNA, potentially sequestering the complex from target DNA. These findings highlight the versatility of anti-CRISPR mechanisms utilized by phages to suppress CRISPR-mediated immune systems.
Topics: Amino Acid Sequence; Bacteria; Bacterial Proteins; Bacteriophages; CRISPR-Cas Systems; Cryoelectron Microscopy; DNA; Models, Molecular; Multiprotein Complexes; Nucleic Acid Conformation; Protein Binding; Protein Conformation; Proteus penneri; RNA, Guide, CRISPR-Cas Systems; Sequence Homology, Amino Acid; Viral Proteins
PubMed: 32483187
DOI: 10.1038/s41467-020-16512-1