Effect of non-rhizospheric bacterial strains on growth of crop plants.

<div><p>Seeds bacterized with respective bacterial strains (approximately1x10⁷cfu/seed, unless otherwise mentioned) were grown <i>in </i><i>vitro</i> in MS medium. After 30 days of growth, shoot height and root length were measured in centimeters, while fresh weight and dry weight of entire plant were measured in milligrams after 30 days of growth. Data represent the mean of the three independent experiments. The vertical line indicates standard error.</p> <p>(A) Effect of five different bacterial strains on growth of tobacco. Treatments included 1. <i>Bacillus </i><i>cereus</i>, 2. <i>B. subtilis</i>, 3. <i>Paenibacillus </i><i>elgii</i>, 4. <i>Stenotrophomonas </i><i>maltophilia</i>, 5. <i>Serratia </i><i>marcescens</i>, and 6. Control, (n=20). Different letters on each bar represent values that were significantly different (p_0.05). (B) Effect of <i>B. cereus</i> on growth of tobacco, tomato, pigeon pea and groundnut (n=24). Data represents percent increase over control. </p> <p>(C) Colonization of <i>B. cereus</i> on tobacco and groundnut roots. Number of days (d) for tobacco: 10, 20, 30 and 40 days of growth and for groundnut: 5, 10, 15 and 20 days of growth (n=20). Students’ t-test of each growth parameter against control for each crop was performed. ** indicate statistically significant at p<0.01, NS =indicate not significant.</p></div

Representative 2DE gels of <i>B. cereus</i> cell-wall proteome.

<p><i>B. cereus</i> grown in MM media amended with (A) tobacco root exudates or (B) groundnut root exudates. In the first dimension (IEF), 500 μg of protein was loaded on an 18 cm IPG strip with a linear gradient of pH 4-7 and 12.5% SDS-PAGE gels were used in the second dimension. Proteins were visualized by Coomasie blue staining. Arrows point towards the differentially expressed proteins. </p

Data_Sheet_1_Features of bacterial and fungal communities in the rhizosphere of Gastrodia elata cultivated in greenhouse for early harvest.docx

Symbiotic microbes are essential for developing and growing Gastrodia elata, an achlorophyllous orchid of high medicinal value. Recently, the cultivation of G. elata in greenhouses has been adopted in Korea to produce mature tubers in a short time. However, no studies have been conducted on the microbial community structure of G. elata cultivated in greenhouse environments. Therefore, we analyzed the temporal features of bacterial and fungal communities in the rhizosphere of G. elata at the juvenile [JT; 2 months after sowing (MAS)], young (YT; 6 MAS), and mature (MT; 11 MAS) tuber stages using culture-dependent and high-throughput sequencing technology. The richness and diversity of the bacterial and fungal communities decreased with tuber growth of G. elata. The symbiotic fungi Mycena sp. and Armillaria sp. as well as tuber extract inhibited the growth of various soil-inhabiting fungal and bacterial strains, indicating that G. elata and its symbiotic fungi play important roles in the selection of rhizosphere microbes. Mortierella rishikesha was the most abundant fungal species in the rhizosphere. We also identified the microorganisms potentially beneficial for G. elata development during greenhouse cultivation. Tubers and symbiotic fungi actively exert selective pressure on rhizosphere microbes, influencing the diversity and abundance of bacterial and fungal communities as G. elata grows. This study is a first report on the temporal microbial community structure of G. elata cultivated in greenhouse. The results on the associated microbiome of G. elata will help understand their beneficial interactions with G. elata and contribute to improvement in cultivation.</p