| Paris polyphylla var.yunnanensis is one of traditional Chinese medicinal materials in China,however its wild resources are scarce.Artificially cultivated P.polyphylla var.yunnanensis has become one of the main sources of this medicinal material in the market.In this study,some of 5-year-old,artificially cultivated P.polyphylla var.yunnanensis were collected from one of the representive planting areas of YunNan,and the diversity of the total endophytic bacteria from the roots,stems and leaves of P.polyphylla var.yunnanensis was investigated by the high-throughput sequencing technology in order to uncover the characteristics and difference of total endophytic bacteria in the three tissues.Subsequently,the cultivable endophytic bacteria were isolated from the the roots,stems and leaves of P.polyphylla var.yunnanensis.The diversity of the cultivable endophytic bacteria from the three tissues was investigated based on their 16 S rDNA sequences,and the characteristics and difference of cultivable endophytic bacteria in the three tissues were analyzed.The correlation between the total endophytic bacteria and the cultivable endophytic bacteria with the polyphyllins contents in the three tissues was then analyzed,and some of significantly correlated bacterial genera were investigated.Finally,all of the cultivable endophytic bacteria in the roots were co-cultured with wheat seedlings,and some of growth-promting bacteria were screened through detecting several growth indexes of these wheat seedlings.The results of this study were as follows:(1)High-throughput sequencing technology was used to analyze the diversity of total endophytic bacteria in the roots,stems,and leaves of P.polyphylla var.yunnanensis,and a total of 802 OTUs were generated.The OTUs of the total endophytic bacteria in the the roots,stems and leaves were 726,139 and 140,respectively,and the total endophytic bacteria in the three tissues were categorized into 232,77 and 63 genera,respectively.The dominant genus of the total endophytic bacteria in the roots,stems and leaves was Serratia,Bacillus and Edaphobacter,respectively.The diversity of total endophytic bacteria in the roots was higher than that in the stems and leaves.The common of the total endophytic bacteria in the three tissues were classified into 26 genera,including Streptococcus,Cupriavidus,and Enterobacter,etc.The total endophytic bacteria only existed in the roots were classified into156 genera,including Steroidobacter,Mesorhizobium,Caulobacter,etc.The total endophytic bacteria only existed in the stems were classified into 77 genera,including Candidatus_Solibacter,Williamsia,Amnibacterium,etc.The total endophytic bacteria only existed in the leaves were classified into 18 genera,including Bryobacter,Georgegenia,and Actinomadura,etc.(2)A total of 747 cultivable endophytic bacteria were isolated from 0.1 g each of the roots,stems and leaves of P.polyphylla var.yunnanensis using two kinds of bacterial media.507,128 and 112 cultivable endophytic bacteria were obtained from the roots,stems and leaves,respectively,and they were classified into 18,14,and 20 genera,respectively.The diversity of cultivable endophytic bacteria in the roots was higher than that in the stems and leaves.The common of the cultivable endophytic bacteria in the three tissues were classified into 3 genera,including Pseudomonas,Bacillus,and Stenotrophomonas.The cultivableendophytic bacteria only existed in the roots were classified into 9 genera,including Pantoea,Citrobacter,Novosphingobium,etc.The cultivable endophytic bacteria only existed in the stems were classified into 7 genera,including Sphingomonas,Carnobacterium,Aerococcus,etc.The cultivable endophytic bacteria only existed in the leaves were classified into 9 genera,including Lysinibacillus,Terribacillus,Aneurinibacillus,etc.The dominant genus of the cultivable endophytic bacteria and the total endophytic bacteria in the roots and stems was same,which was Serritia and Bacillus,respectively.The dominant genus of the cultivable endophytic bacteria in the leaves was Brevibacillus,however that of the total endophytic bacteria in the leaves was Edaphobacter.(3)The correlation of the common of the total endophytic bacteria(26 genera)in the roots,stems and leaves of P.polyphylla var.yunnanensis with four polyphyllins contents in the three tissues was analyzed,and three genera were found to be significantly correlated with four polyphyllins contents.The polyphyllin VI content and polyphyllin II content were significantly positive correlation with the Streptococcus and Enhydrobacter in the roots.However,the polyphyllin VII content was significantly negative correlation with the Streptococcus and Enhydrobacter in the roots.The polyphyllin VI content and polyphyllin II content was significantly positive correlation with the Janibacter in the stems.The contents of polyphyllin VI and polyphyllin II were significantly negative correlation with the Janibacter in the stems.The total endophytic bacteria in the leaves were not correlation with their polyphyllins content.The polyphyllin I content in the three tissues was not correlation with their total endophytic bacteria in the three tissues.Additionally,the correlation between 38 genera of the cultivable endophytic bacteria obtained in this study with the polyphyllins content was analyzed,and none of significant correlations were observed.(4)Through co-cultivation of all cultivable endophytic bacteria in the roots with wheat seedlings,10 growh-promoting endophytic bacteria were obtained.The YNR32041(Alcaligenes)strain had a most significant promoting effect on the root length of wheat seedlings,the growth rate of the root length of co-cultivated wheat seedlings was 602.51%compared to the control(2.8±0.4 cm).The YNR32016(Enterobacter)strain had a most significant promoting effect on the plant height of wheat seedlings,the growth rate of the plant height of co-cultivated wheat seedlings was 72.43% compared to the control(9.69±1.4cm).The YNR32046(Bacillus)strain had a most significant promoting effect on the stem thickness of wheat seedlings,the growth rate of the stem thickness of co-cultivated wheat seedlings was 26.87% compared to the control(1.85±0.43 cm).Verification of the promoting effect of the YNR32041(Alcaligenes)strain was performed,and the promoting effect of YNR32041 on wheat seedlings was found to be significant(P <0.01),and the most obvious promoting effect was observed on the 10 d after co-culturation. |
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