Integrated Effect of Algal Biochar and Plant Growth Promoting Rhizobacteria on Physiology and Growth of Maize Under Deficit Irrigations

The population acceleration and better lifestyle submit new challenges for wheat researchers to breed wheat (Triticum sativum) cultivars with upgraded yield, quality, and resistance against abiotic stresses such as drought, so exploiting all available natural relatives of cultivated wheat and introducing even sensitive ones may be a useful approach to save time and efforts. Normally, the seedling stage is highly drought vulnerable, but for sensitive cultivars, the situation is more frustrating. We examine the potentiality of two regulating hormones in the upregulation of two wheat cultivars varying in their drought susceptibility at the seedling stage comparatively evaluated by morpho-physiological traits as indicators of drought tolerance. All the studied traits revealed cultivardependent variation in response to water deficit where cv. Sids 1 was tolerant and cv. Beni-suef 5 was sensitive. Shoot/root ratio, total water content, total dry weight, chlorophyll stability, total osmotic potential, osmoregulatory components, viz., soluble carbohydrates, soluble proteins and proline, membrane damage trait in terms of LOX, antioxidant defense system enzymatically in terms of APX, CAT, POD, SOD, and total antioxidant as drought tolerance indicators were the troubling shot due to water shortage in both cultivars. The damaging impacts of water deficit on these traits were conceived for sensitive cultivar compared with the tolerant one. Exogenous application of jasmonic acid (JA) or kinetin (K) efficiently conferred drought tolerance to sensitive cultivar to withstand harsh conditions in earlier stages and to perform comparably with tolerant ones. Applied hormones prompted unequivocal inversion from a state of downregulation to upregulation regarding all drought tolerance traits via reallocation of photoassimilates to vegetative sinks, thus promoting growth, increasing the accumulation of some osmoregulation compounds and thus increased tissue vigor and regulated the activity of antioxidant enzymes as well as morphological modulation attained by the restoration of shoot/root ratio. The results would promisingly be supportive of research programs seeking to develop antidrought stress practices for sensitive wheat cultivars.

Section: Discussionsupporting

confidence: 91%

Effect of Exogenously Applied Jasmonic Acid and Kinetin on Drought Tolerance of Wheat Cultivars Based on Morpho-Physiological Evaluation

Abeed

Eissa

Abdel-Wahab

2020

“…However, to guarantee wheat production, the use of chemical fertilizers and pesticides is a common agronomic practice that is recognized to have negative effects on the environment and human health (Curtis and Halford 2014). In this context, the use of beneficial microorganisms (e.g., plant growth-promoting rhizobacteria [PGPR]) has emerged as an attractive alternative to ensure crop survival and maintain food security worldwide (Gouda et al 2018;Ullah et al 2019). Chile is not an exception, and native microorganisms also represent a biotechnological tool to guarantee wheat production.…”

Section: Introductionmentioning

confidence: 99%

In Situ Cultivation Approach to Increase the Culturable Bacterial Diversity in the Rhizobiome of Plants

Acuña

Marileo

Araya

et al. 2020

The use of high-throughput DNA sequencing (HTS) has revealed the great diversity of rhizobacteria in plant rhizospheres; however, only a minor portion (≤ 1%) of rhizobacteria belonging to few taxa can be cultured under laboratory conditions. In recent years, in situ cultivation has opened a window to explore a greater diversity of bacterial taxa in the environment. Here, we explored the total and culturable rhizobacterial communities associated with the rhizosphere of wheat plants by using 16S rRNAbased HTS and in situ cultivation with microwell chambers (MWCs), respectively. Results by HTS revealed to phyla Proteobacteria (29-39%), Acidobacteria (17%), Actinobacteria (11-15%), and Bacteroidetes (5-12%) as the most abundant rhizobacterial taxa in rhizosphere samples. A total of 206 isolates (26 genera) were obtained with MWCs, where coincidentally with HTS, the most abundant phyla were Proteobacteria (70.4%), Firmicutes (24%), Actinobacteria (4%), and Bacteroidetes (1.5%). At the genus level, the most of isolates (72%) belonged to Pseudomonas, followed by Bacillus, Stenotrophomonas, Delftia, and Herbaspirillum. Members of rare taxa (Lelliottia, Rhodococcus, Micrococcus, Variovorax, and Bosea) also were isolated by MWCs. In addition, a high proportion (82%) of isolates showed high similarity with plant beneficial and environmental non-pathogenic bacteria whereas a minor proportion (18%) of isolates showed high similarity to human and plant pathogenic bacteria. This study demonstrates that in situ cultivation represents a useful tool to isolate a greater number of rhizobacterial taxa, which can be investigated under laboratory conditions in bioprospecting (e.g., plant growth-promoting bacteria) and public health (e.g., human opportunist and plant pathogens) studies.

“…This reduction is less in the case of turfs inoculated with Pf. In the same vein, Ullah et al (2019) also found that inoculation with PGPR increases P content of maize compared with control treatment under drought stress. P, as an essential macronutrient, has a special place in the growth and development of plants.…”

Section: Discussionmentioning

confidence: 68%

“…Therefore, by increasing root efficiency, the water efficiency by plants under stress is increased and results in an increase in TQ, FW, and RWC (Miransari 2014). For instance, as reported by Ullah et al (2019), PGPR significantly enhanced FW in maize under deficit irrigations compared with respective controls.…”

Section: Discussionmentioning

confidence: 74%

Morpho-Physiological and Biochemical Attributes of Tall Fescue (Festuca arundinacea Schreb.) Inoculated with Pseudomonas fluorescens under Deficit Irrigation

Mahdavi

Salehi

Zarei

2020

Urban green spaces are a form of land use that often require intensive maintenance and have social and ecological functions. Due to global water scarcity, management strategies regarding planting and maintenance vegetation, especially turfgrass, are changing in many countries. Tall fescue serves as one of the most important and commonly used cool-season turfgrass species and is considered to be drought tolerant. Plant growth-promoting rhizobacteria (PGPR), as bio-fertilizers, are also crucial in terms of decreasing and improving harmful effects of abiotic stresses in plants. This research considers inoculation with PGPR in turfgrass for the purpose of improving drought tolerance and reducing water consumption. This work was conducted over two consecutive years to study the effects of Pseudomonas fluorescens on two cultivars of tall fescue ('H-d' and 'J-r') with three irrigation intervals (7, 14, and 21 days) under greenhouse and outdoor conditions. Results showed that irrigating less frequently caused a reduction in tall fescue turf quality, fresh weight, chlorophyll content, relative water content, and phosphorus content. In most cases, the quantity of compatible solutes (proline and glycine betaine) and antioxidant enzymes (superoxide dismutase and peroxidase) was increased; however, the rate of change was enhanced in turfgrass treated with PGPR. Quantitative and qualitative characteristics of turfgrass in greenhouse experiment were substantially superior in comparison with outdoor condition. This research is novel, as it is the first quantitative and qualitative study to the best of our knowledge exploring the effect of PGPR on turfgrass biomass. The level of amino acids, the activity rate of antioxidant enzymes, and the bacterium effects on turfgrass have been considered, both under greenhouse conditions and outdoor environment. This research provides a methodology to investigate various beneficial bacteria on turfgrass for the purpose of developing better management programs under stress conditions.