Browsing by Author "Hou, Guichuan"

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    Growth promotion and colonization of switchgrass (Panicum virgatum) cv. Alamo by bacterial endophyte Burkholderia phytofirmans strain PsJN
    Kim, Seonhwa; Lowman, James Scott; Hou, Guichuan; Nowak, Jerzy; Flinn, Barry; Mei, Chuansheng (2012-05-30)
    Background Switchgrass is one of the most promising bioenergy crop candidates for the US. It gives relatively high biomass yield and can grow on marginal lands. However, its yields vary from year to year and from location to location. Thus it is imperative to develop a low input and sustainable switchgrass feedstock production system. One of the most feasible ways to increase biomass yields is to harness benefits of microbial endophytes. Results We demonstrate that one of the most studied plant growth promoting bacterial endophytes, Burkholderia phytofirmans strain PsJN, is able to colonize and significantly promote growth of switchgrass cv. Alamo under in vitro, growth chamber, and greenhouse conditions. In several in vitro experiments, the average fresh weight of PsJN-inoculated plants was approximately 50% higher than non-inoculated plants. When one-month-old seedlings were grown in a growth chamber for 30 days, the PsJN-inoculated Alamo plants had significantly higher shoot and root biomass compared to controls. Biomass yield (dry weight) averaged from five experiments was 54.1% higher in the inoculated treatment compared to non-inoculated control. Similar results were obtained in greenhouse experiments with transplants grown in 4-gallon pots for two months. The inoculated plants exhibited more early tillers and persistent growth vigor with 48.6% higher biomass than controls. We also found that PsJN could significantly promote growth of switchgrass cv. Alamo under sub-optimal conditions. However, PsJN-mediated growth promotion in switchgrass is genotype specific. Conclusions Our results show B. phytofirmans strain PsJN significantly promotes growth of switchgrass cv. Alamo under different conditions, especially in the early growth stages leading to enhanced production of tillers. This phenomenon may benefit switchgrass establishment in the first year. Moreover, PsJN significantly stimulated growth of switchgrass cv. Alamo under sub-optimal conditions, indicating that the use of the beneficial bacterial endophytes may boost switchgrass growth on marginal lands and significantly contribute to the development of a low input and sustainable feedstock production system.
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    A Potential Application of Pseudomonas psychrotolerans IALR632 for Lettuce Growth Promotion in Hydroponics
    Mei, Chuansheng; Zhou, Dongfang; Chretien, Robert L.; Turner, Amy; Hou, Guichuan; Evans, Michael R.; Lowman, Scott (MDPI, 2023-02-02)
    Controlled environment agriculture hydroponic systems grow plants year-round without restriction from outside environmental conditions. In order to further improve crop yield, plant growth-promoting bacteria were tested on hydroponically grown lettuce (Lactuca sativa) plants. From our bacterial endophyte library, we found one bacterium, Pseudomonas psychrotolerans IALR632, that is promising in promoting lettuce growth in multiple hydroponic systems. When Green Oakleaf lettuce seeds were inoculated with IALR632 during germination, IALR632 significantly increased lateral root development by 164%. When germinated seedlings were inoculated with IALR632 and then transplanted to different hydroponic systems, shoot and root fresh weights of Green Oakleaf increased by 55.3% and 17.2% in a nutrient film technique (NFT) system in the greenhouse, 13.5% and 13.8% in an indoor vertical NFT system, and 15.3% and 13.6% in a deep water cultivation (DWC) system, respectively. IALR632 also significantly increased shoot fresh weights of Rex by 33.9%, Red Oakleaf by 21.0%, Red Sweet Crisp by 15.2%, and Nancy by 29.9%, as well as Red Rosie by 8.6% (no significant difference). Inoculation of IALR632-GFP and subsequent analysis by confocal microscopy demonstrated the endophytic nature and translocation from roots to shoots. The results indicate that P. psychrotolerans IALR632 has a potential application in hydroponically grown lettuce plants.