Endophytic Bacteria And Rhizosphere Microorganisms And Biological Functional Diversity Of Hybrid Pennisetum

Pennisetum is an important forage resource,with the advantages of high yield,high resistance to advance condition,quick regeneration capacity,free from diseases and pest,it has been widely cultivated in tropical and subtropical areas mainly used as forge crop.This study intends to Hybrid Pennisetum endophytic bacteria and rhizosphere microorganisms as the research object,aim to screen the microorganisms with the function of promoting growth and antagonism,and to investigate the relationship between the endophytic bacteria,rhizosphere microorganisms and the resistance to diseases and insect pests.The research aimed to provide scientific basis for the screening of beneficial microorganism resources which can promote the development of plant disease resistance.We isolated more than 120 strains of Hybrid Pennisetum endophytic bacteria and rhizosphere microorganisms(27 strains of rhizosphere bacteria,64 strains of rhizosphere actinomycetes and 32 strains of endophytic fungi).Quantitative statistics of microorganisms found that bacteria are the main types of microorganism,accounted for 82.60%-85.80% of the total;followed by actinomycetes,the number of microorganisms in the total number of11.73%-14.28%;while Minimum number of fungi accounted for 2.47%-3.10%.16S rRNA sequencing and phylogenetic tree construction have shown that Bacteria and actinomycetes belong to 4 phylums,16 families,23 genera,pseudomonas is the dominant genus(18.75%);fungi belong to 1 phylum,3 families,4 genus,Aspergillus(35.71%),Cadosporium(35.71%)are the dominant genus.The bacteriostasis experiment(six fungal phytopathogens,three bacterial phytopathogens,one algae)were studied.Most of the bacteria have shown antagonistic activities against Cytospora mandshurica(70.37%)?Pellicularia sasakii(66.67%),LCX23 showed seven antibacterial activities,especially LCX20,LCX23 had obvious inhibitory effect on Xanthomonas axonopodis pv.Citri(antibacterial zone diameter greater than 10 mm),LCX24,LCX28 had obvious inhibitory effect on Ralstonia solanacearum(antibacterial zone diameter greater than 15 mm).Most of the actinomycetes have shown antagonistic activities against Pellicularia sasakii(68.75%)?Sclerotinia sclerotiorum(64.06%)?Gloeosporium fructigenum(60.94%),the antagonistic effect of actinomyces to Xanthomonas axonopodis pv.Citri was significantly higher than that of other 2 bacterial pathogens.LCG 62(95.83%),LCG47(88.89%),LCG 78(86.81%)can significantly inhibit the growth of Microcystis aeruginosa.The antagonistic effect of fungi was relatively weaker than bacteria and actinomycetes.In the promotion experiment,81.48% bacterial strain produced siderophore,70.37% of the strains produced indole acetic hormone(IAA),59.26% of the bacterial isolates have shown nitrogen fixation potential and phosphate solubilization activity has been shown by55.56% of the isolates.17 strains of bacteria showed at least three kinds of growth promoting effect,and 7 strains showed all of the 4 kinds of growth promoting effects.The highest specific IAA production was observed in strain LCX 22 at 73.67 ?g/mL,and solubilization ability of strain LCX 2 is the best.In pot experiments,plant treated with a single or strains mixture were taller compared to the untreated control with significantly enhanced root length,shoot fresh weight and shoot dry weight.These results indicate that the three isolates,mixture-1 and mixture-2,particularly LCX 23 can significantly promote the growth of rice,thus,they could be used to facilitate an effective plant growth promotion in rice plants.