Soil and root microbiome analysis and isolation of plant growth-promoting bacteria from hybrid buffaloberry (Shepherdia utahensis 'Torrey') across three locations.

The effects of climate change are becoming increasingly hazardous for our ecosystem. Climate resilient landscaping, which promotes the use of native plants, has the potential to simultaneously decrease the rate of climate change, enhance climate resilience, and combat biodiversity losses. Native plants and their associated microbiome form a holo-organism; interaction between plants and microbes is responsible for plants' growth and proper functioning. In this study, we were interested in exploring the soil and root microbiome composition associated with Shepherdia utahensis, a drought hardy plant proposed for low water use landscaping, which is the hybrid between two native hardy shrubs of Utah, S. rotudifolia and S. argentea. The bulk soil, rhizosphere, root, and nodule samples of the hybrid Shepherdia plants were collected from three locations in Utah: the Logan Campus, the Greenville farm, and the Kaysville farm. The microbial diversity analysis was conducted, and plant growth-promoting bacteria were isolated and characterized from the rhizosphere. The results suggest no difference in alpha diversity between the locations; however, the beta diversity analysis suggests the bacterial community composition of bulk soil and nodule samples are different between the locations. The taxonomic classification suggests Proteobacteria and Actinobacteriota are the dominant species in bulk soil and rhizosphere, and Actinobacteriota is solely found in root and nodule samples. However, the composition of the bacterial community was different among the locations. There was a great diversity in the genus composition in bulk soil and rhizosphere samples among the locations; however, Frankia was the dominant genus in root and nodule samples. Fifty-nine different bacteria were isolated from the rhizosphere and tested for seven plant growth-promoting (PGP) traits, such as the ability to fix nitrogen, phosphates solubilization, protease activity, siderophore, Indole Acetic Acid (IAA) and catalase production, and ability to use ACC as nitrogen source. All the isolates produced some amount of IAA. Thirty-one showed at least four PGP traits and belonged to Stenotrophomonas, Chryseobacterium, Massilia, Variovorax, and Pseudomonas. We shortlisted 10 isolates that showed all seven PGP traits and will be tested for plant growth promotion.

IAA-producing plant growth promoting rhizobacteria from Ceanothus velutinus enhance cutting propagation efficiency and Arabidopsis biomass.

Climate-induced drought impacts plant growth and development. Recurring droughts increase the demand for water for food production and landscaping. Native plants in the Intermountain West region of the US are of keen interest in low water use landscaping as they are acclimatized to dry and cold environments. These native plants do very well at their native locations but are difficult to propagate in landscape. One of the possible reasons is the lack of associated microbiome in the landscaping. Microbiome in the soil contributes to soil health and impacts plant growth and development. Here, we used the bulk soil from the native plant Ceanothus velutinus (snowbrush ceanothus) as inoculant to enhance its propagation. Snowbrush ceanothus is an ornamental plant for low-water landscaping that is hard to propagate asexually. Using 50% native bulk soil as inoculant in the potting mix significantly improved the survival rate of the cuttings compared to no-treated cuttings. Twenty-four plant growth-promoting rhizobacteria (PGPR) producing indole acetic acid (IAA) were isolated from the rhizosphere and roots of the survived snowbrush. Seventeen isolates had more than 10µg/mL of IAA were shortlisted and tested for seven different plant growth-promoting (PGP) traits; 76% showed nitrogen-fixing ability on Norris Glucose Nitrogen free media,70% showed phosphate solubilization activity, 76% showed siderophore production, 36% showed protease activity, 94% showed ACC deaminase activity on DF-ACC media, 76% produced catalase and all of isolates produced ammonia. Eight of seventeen isolates, CK-6, CK-22, CK-41, CK-44, CK-47, CK-50, CK-53, and CK-55, showed an increase in shoot biomass in Arabidopsis thaliana. Seven out of eight isolates were identified as Pseudomonas, except CK-55, identified as Sphingobium based on 16S rRNA gene sequencing. The shortlisted isolates are being tested on different grain and vegetable crops to mitigate drought stress and promote plant growth.

Effect of different levels of gibberellic acid and kinetin on quality and self-life of banana (Musa spp.) fruits.

Artificial fruit ripening agents have become increasingly popular in recent years. During the off-seasons, various ripening agents are used for the ripening of banana fruits. The effects of various ripening agents of banana fruits (variety: Malbhog) were studied. Seven treatments consisting of distilled water, Gibberellic acid (GA3) @ 100 ppm, GA3 @ 200 ppm, GA3 @ 300 ppm, kinetin @ 3 ppm, kinetin @ 5 ppm, and kinetin @ 7 ppm were laid out in a Completely Randomized Design with three replications. The maximum loss in weight (9.195%), Total Soluble Solids (20.33˚B), the highest color score (6), pH (4.767), Total Soluble Solids/Titratable Acidity TA (34.23), and Pulp peel ratio (2.84) were observed in banana sprayed with distilled water whereas the minimum value for TSS (12.67˚B), pulp peel ratio (1.813), peel color rating (2.67), TSS/TA (15.32) were observed in GA3 @ 300 ppm treated fruits. The maximum (32.67 days) and the minimum (18.33 days) shelf-life was observed in GA3 @ 300 ppm and distilled water respectively. This research will help in the regulation of ripening as per the needs of consumers and the distance of the market. In horticulture, it will help to extend storage life and reduce quality and economic loss.

A Proposed Method for Simultaneous Measurement of Cuticular Transpiration From Different Leaf Surfaces in Camellia sinensis.

The plant cuticle is the major barrier that limits unrestricted water loss and hence plays a critical role in plant drought tolerance. Due to the presence of stomata on the leaf abaxial surface, it is technically challenging to measure abaxial cuticular transpiration. Most of the existing reports were only focused on leaf astomatous adaxial surface, and few data are available regarding abaxial cuticular transpiration. Developing a method that can measure cuticular transpiration from both leaf surfaces simultaneously will improve our understanding about leaf transpiration barrier organization. Here, we developed a new method that enabled the simultaneous measurement of cuticular transpiration rates from the adaxial and abaxial surfaces. The proposed method combined multi-step leaf pretreatments including water equilibration under dark and ABA treatment to close stomata, as well as gum arabic or vaseline application to remove or seal the epicuticular wax layer. Mathematical formulas were established and used to calculate the transpiration rates of individual leaf surfaces from observed experimental data. This method facilitates the simultaneous quantification of cuticular transpiration from adaxial and abaxial leaf surfaces. By applying this method, we demonstrated that the adaxial intracuticular waxes and the abaxial epicuticular waxes constitute the major transpiration barriers in Camellia sinensis. Wax analysis indicated that adaxial intracuticular waxes had higher coverage of very long chain fatty acids, 1-alkanol esters, and glycols, which may be attributed to its higher transpiration barrier than that of the abaxial intracuticular waxes.