Mitigation Effect of Drought Stress by Plant Growth-promoting Bacterium Bacillus sp. SB19 on Kale Seedlings in Greenhouse

AbstractWater deficit has devastating impacts on legume production, particularly with the current abrupt climate changes in arid environments. The application of plant growth-promoting rhizobacteria (PGPR) is an effective approach for producing natural nitrogen and attenuating the detrimental effects of drought stress. This study investigated the influence of inoculation with the PGPR Rhizobium leguminosarum biovar viciae (USDA 2435) and Pseudomonas putida (RA MTCC5279) solely or in combination on the physio-biochemical and agronomic traits of five diverse Vicia faba cultivars under well-watered (100% crop evapotranspiration [ETc]), moderate drought (75% ETc), and severe drought (50% ETc) conditions in newly reclaimed poor-fertility sandy soil. Drought stress substantially reduced the expression of photosynthetic pigments and water relation parameters. In contrast, antioxidant enzyme activities and osmoprotectants were considerably increased in plants under drought stress compared with those in well-watered plants. These adverse effects of drought stress reduced crop water productivity (CWP) and seed yield‐related traits. However, the application of PGPR, particularly a consortium of both strains, improved these parameters and increased seed yield and CWP. The evaluated cultivars displayed varied tolerance to drought stress: Giza-843 and Giza-716 had the highest tolerance under well-watered and moderate drought conditions, whereas Giza-843 and Sakha-4 were more tolerant under severe drought conditions. Thus, co-inoculation of drought-tolerant cultivars with R. leguminosarum and P. putida enhanced their tolerance and increased their yield and CWP under water-deficit stress conditions. This study showed for the first time that the combined use of R. leguminosarum and P. putida is a promising and ecofriendly strategy for increasing drought tolerance in legume crops.

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Complete Genome Sequence of Bacillus sp. strain WR11, an Endophyte Isolated from Wheat Root Providing Genomic Insights into Its Plant Growth-Promoting Effects

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi-02-20-0030-a ◽

2020 ◽

Vol 33 (7) ◽

pp. 876-879

Author(s):

Can Chen ◽

Zonghao Yue ◽

Cuiwei Chu ◽

Keshi Ma ◽

Lili Li ◽

...

Keyword(s):

Plant Growth ◽

Genome Sequence ◽

Complete Genome Sequence ◽

Complete Genome ◽

Prokaryotic Genome ◽

Wheat Root ◽

Bacillus Sp ◽

Symbiotic Interaction ◽

Plant Growth Promoting ◽

Growth Promoting

Bacillus sp. strain WR11 isolated from the root of wheat (Triticum aestivum L.) possesses abiotic stress alleviating properties and produces several types of enzymes. However, its genomic information is lacking. The study described the complete genome sequence of the bacterium. The size of the genome was 4 202 080 base pairs that consisted of 4 405 genes in total. The G+C content of the circular genome was 43.53% and there were 4 170 coding genes, 114 pseudo genes, 30 ribosome RNAs, 86 tRNAs, and 5 ncRNAs, based on the Prokaryotic Genome Annotation Pipeline (PGAP). Many genes were related to the stress-alleviating properties and 124 genes existed in the CAZy database. The complete genome data of strain WR11 will provide valuable resources for genetic dissection of its plant growth-promoting function and symbiotic interaction with plant.

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Interactive Effects of Plant Growth-Promoting Rhizobacteria and Phosphates Sources on Growth and Phosphorus Nutrition of Soybean under Moderate Drought

Notulae Botanicae Horti Agrobotanici Cluj-Napoca ◽

10.15835/nbha47311371 ◽

2019 ◽

Vol 47 (3) ◽

Author(s):

Vladimir Ion ROTARU ◽

Luxita RISNOVEANU

Keyword(s):

Drought Stress ◽

Plant Growth ◽

Water Supply ◽

Nutrient Uptake ◽

Burkholderia Cepacia ◽

Plant Growth Promoting Rhizobacteria ◽

P Nutrition ◽

Moderate Drought ◽

Plant Growth Promoting ◽

Growth Promoting

The growth of legume plants is usually improved by the rhizobacteria inoculation under low phosphorus (P) and alleviation of P nutrition plays important role in plant drought stress response. The aim of this study was to assess the comparative efficacy of two plant growth promoting rhizobacteria namely Burkholderia cepacia B36 and Enterobacter radicincitans D5/23T combined with two sources of phosphates in soybean (Glycine max L.) under low water supply. Plants were grown under P soluble versus insoluble P fertilization for comparing the effects of soybean inoculation on growth, uptake and use efficiency of phosphorus under moderate drought stress. At the beginning of flowering, half of plants was subjected to low water supply (35% water holding capacity, WHC) for 12 days while control plants were well watered - 70% WHC. The plants were harvested at the end of drought and physiological traits and P contents were analyzed. The inoculation treatments showed better plant growth and nutrient uptake when compared to uninoculated control. The application of the Burkholderia cepacia was more efficiently in terms plant growth than E. radicincitans especially under insoluble phosphates. Phosphorus concentrations of shoots and roots increased with both bacterial strains. The bacterial inoculation has much better stimulatory effect on nutrient uptake by soybean fertilized with insoluble phosphates. Study findings indicate that the combined application of PGPR (Burkholderia cepacia B36) and P amendments has the potential to improve P nutrition and growth of soybean cultivated on P-deficient soil under well-watered as well as moderate drought condition. ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

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Effects of the Biofertilizer OYK (Bacillus sp.) Inoculation on Endophytic Microbial Community in Sweet Potato

Horticulturae ◽

10.3390/horticulturae6040081 ◽

2020 ◽

Vol 6 (4) ◽

pp. 81

Author(s):

Ahsanul Salehin ◽

Md Hafizur Rahman Hafiz ◽

Shohei Hayashi ◽

Fumihiko Adachi ◽

Kazuhito Itoh

Keyword(s):

Plant Growth ◽

Sweet Potato ◽

Bacterial Communities ◽

Ipomoea Batatas ◽

Diversity Index ◽

Plant Growth Promoting Bacteria ◽

Bacillus Sp ◽

Bacterial Composition ◽

Plant Growth Promoting ◽

Growth Promoting

Sweet potato (Ipomoea batatas L.) grows well even in infertile and nitrogen-limited fields, and endophytic bacterial communities have been proposed to be responsible for this ability. Plant-growth-promoting bacteria are considered eco-friendly and are used in agriculture, but their application can interact with endophytic communities in many ways. In this study, a commercial biofertilizer, OYK, consisting of a Bacillus sp., was applied to two cultivars of sweet potato, and the effects on indigenous endophytic bacterial communities in field conditions were examined. A total of 101 bacteria belonging to 25 genera in 9 classes were isolated. Although the inoculated OYK was not detected and significant plant-growth-promoting effects were not observed, the inoculation changed the endophytic bacterial composition, and the changes differed between the cultivars, as follows: Novosphingobium in α-Proteobacteria was dominant; it remained dominant in Beniharuka after the inoculation of OYK, while it disappeared in Beniazuma, with an increase in Sphingomonas and Sphingobium in α-Proteobacteria as well as Chryseobacterium and Acinetobacter in Flavobacteria. The behavior of Bacilli and Actinobacteria also differed between the cultivars. The Shannon diversity index (H) increased after inoculation in all conditions, and the values were similar between the cultivars. Competition of the inoculant with indigenous rhizobacteria and endophytes may determine the fates of the inoculant and the endophytic community.

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