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Mishra A, Gupta R, Joshi RK, Garkoti SC. Topography-mediated light environment regulates intra-specific seasonal and diurnal patterns of photosynthetic plasticity and plant ecophysiological adaptation strategies. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2024; 30:435-452. [PMID: 38633276 PMCID: PMC11018732 DOI: 10.1007/s12298-024-01439-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 12/20/2023] [Accepted: 03/16/2024] [Indexed: 04/19/2024]
Abstract
Due to substantial topographic variations in the Himalaya, incident solar radiation in the forest canopy is highly unequal. This results in significant environmental differences at finer scales and may lead to considerable differences in photosynthetic productivity in montane forests. Therefore, local-scale ecophysiological investigations, may be more effective and instructive than landscape-level inventories and models. We investigated leaf ecophysiological differences and related adaptations between two Quercus semecarpifolia forests in aspect-mediated, significantly varying light regimes in the same mountain catchment. Seasonal and diurnal rates of photosynthesis (A) were significantly higher in south aspect (S) than the north (N). Although temperature was a key contributor to seasonal fluctuations in photosynthetic physiology, photoperiod significantly determined intraspecific variations in seasonal and diurnal plasticity of leaf ecophysiological traits between the two topography-mediated light environments. The regression model for A as a function of stomatal conductivity (gsw) explained the critical role of gsw in triggering photosynthetic plasticity as an adaptive function against varying environmental stresses due to seasonal solar differences. We also examined, modifications in chlorophyll content between the two light regimes across seasons to determine the chlorophyll adaptation strategy. The N aspect had higher leaf chl a, b, and chl a + b and a lower chl-allocation ratio (a/b) than S, which helped to optimize the required light reception in the photoreaction centers for improved photosynthetic performance. The leaf light response curves for A and gsw were observed against varying incident photosynthetic photon flux densities (0-2000 mol.m2 s-1 PPFD) for both aspects. We found that the same species developed significantly distinct light response strategies and photosynthetic capacities in S than in N for the given magnitudes of PPFD. Such acquired ecophysiological adaptations owing to varying light environments may provide significant clues for understanding the impact of future climate change on Himalayan tree species.
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Affiliation(s)
- Ambuj Mishra
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Rajman Gupta
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Rajendra Kr. Joshi
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
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Malhotra P, Basu S, Lee BW, Oeller L, Crowder DW. Effects of Soil Rhizobia Abundance on Interactions between a Vector, Pathogen, and Legume Plant Host. Genes (Basel) 2024; 15:273. [PMID: 38540332 PMCID: PMC10970239 DOI: 10.3390/genes15030273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 02/13/2024] [Accepted: 02/20/2024] [Indexed: 06/15/2024] Open
Abstract
Soil rhizobia promote nitrogen fixation in legume hosts, maximizing their tolerance to different biotic stressors, plant biomass, crop growth, and yield. While the presence of soil rhizobia is considered beneficial for plants, few studies have assessed whether variation in rhizobia abundance affects the tolerance of legumes to stressors. To address this, we assessed the effects of variable soil rhizobia inoculum concentrations on interactions between a legume host (Pisum sativum), a vector insect (Acyrthosiphon pisum), and a virus (Pea enation mosaic virus, PEMV). We showed that increased rhizobia abundance reduces the inhibitory effects of PEMV on the nodule formation and root growth in 2-week-old plants. However, these trends were reversed in 4-week-old plants. Rhizobia abundance did not affect shoot growth or virus prevalence in 2- or 4-week-old plants. Our results show that rhizobia abundance may indirectly affect legume tolerance to a virus, but effects varied based on plant age. To assess the mechanisms that mediated interactions between rhizobia, plants, aphids, and PEMV, we measured the relative expression of gene transcripts related to plant defense signaling. Rhizobia concentrations did not strongly affect the expression of defense genes associated with phytohormone signaling. Our study shows that an abundance of soil rhizobia may impact a plant's ability to tolerate stressors such as vector-borne pathogens, as well as aid in developing sustainable pest and pathogen management systems for legume crops. More broadly, understanding how variable rhizobia concentrations can optimize legume-rhizobia symbiosis may enhance the productivity of legume crops.
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Affiliation(s)
| | - Saumik Basu
- Department of Entomology, Washington State University, Pullman, WA 99164, USA; (P.M.); (B.W.L.); (L.O.); (D.W.C.)
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Anand U, Pal T, Yadav N, Singh VK, Tripathi V, Choudhary KK, Shukla AK, Sunita K, Kumar A, Bontempi E, Ma Y, Kolton M, Singh AK. Current Scenario and Future Prospects of Endophytic Microbes: Promising Candidates for Abiotic and Biotic Stress Management for Agricultural and Environmental Sustainability. MICROBIAL ECOLOGY 2023; 86:1455-1486. [PMID: 36917283 PMCID: PMC10497456 DOI: 10.1007/s00248-023-02190-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
Globally, substantial research into endophytic microbes is being conducted to increase agricultural and environmental sustainability. Endophytic microbes such as bacteria, actinomycetes, and fungi inhabit ubiquitously within the tissues of all plant species without causing any harm or disease. Endophytes form symbiotic relationships with diverse plant species and can regulate numerous host functions, including resistance to abiotic and biotic stresses, growth and development, and stimulating immune systems. Moreover, plant endophytes play a dominant role in nutrient cycling, biodegradation, and bioremediation, and are widely used in many industries. Endophytes have a stronger predisposition for enhancing mineral and metal solubility by cells through the secretion of organic acids with low molecular weight and metal-specific ligands (such as siderophores) that alter soil pH and boost binding activity. Finally, endophytes synthesize various bioactive compounds with high competence that are promising candidates for new drugs, antibiotics, and medicines. Bioprospecting of endophytic novel secondary metabolites has given momentum to sustainable agriculture for combating environmental stresses. Biotechnological interventions with the aid of endophytes played a pivotal role in crop improvement to mitigate biotic and abiotic stress conditions like drought, salinity, xenobiotic compounds, and heavy metals. Identification of putative genes from endophytes conferring resistance and tolerance to crop diseases, apart from those involved in the accumulation and degradation of contaminants, could open new avenues in agricultural research and development. Furthermore, a detailed molecular and biochemical understanding of endophyte entry and colonization strategy in the host would better help in manipulating crop productivity under changing climatic conditions. Therefore, the present review highlights current research trends based on the SCOPUS database, potential biotechnological interventions of endophytic microorganisms in combating environmental stresses influencing crop productivity, future opportunities of endophytes in improving plant stress tolerance, and their contribution to sustainable remediation of hazardous environmental contaminants.
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Affiliation(s)
- Uttpal Anand
- Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 8499000, Midreshet Ben-Gurion, Israel.
| | - Tarun Pal
- Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 8499000, Midreshet Ben-Gurion, Israel
| | - Niraj Yadav
- French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sde Boker Campus, 8499000, Midreshet Ben-Gurion, Israel
| | - Vipin Kumar Singh
- Department of Botany, K.S. Saket P.G. College, Ayodhya affiliated to Dr. Rammanohar Lohia Avadh University, Ayodhya, 224123, Uttar Pradesh, India
| | - Vijay Tripathi
- Department of Molecular and Cellular Engineering, Jacob Institute of Biotechnology and Bioengineering, Sam Higginbottom University of Agriculture, Technology and Sciences, Prayagraj, 211007, Uttar Pradesh, India
| | - Krishna Kumar Choudhary
- Department of Botany, Mahila Mahavidyalaya, Banaras Hindu University, Varanasi, 221005, Uttar Pradesh, India
| | - Awadhesh Kumar Shukla
- Department of Botany, K.S. Saket P.G. College, Ayodhya affiliated to Dr. Rammanohar Lohia Avadh University, Ayodhya, 224123, Uttar Pradesh, India
| | - Kumari Sunita
- Department of Botany, Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, Uttar Pradesh, 273009, India
| | - Ajay Kumar
- Department of Postharvest Science, Agricultural Research Organization, The Volcani Center, P.O. Box 15159, 7505101, Rishon, Lezion, Israel
| | - Elza Bontempi
- INSTM and Chemistry for Technologies Laboratory, University of Brescia, Via Branze 38, 25123, Brescia, Italy.
| | - Ying Ma
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, 3000-456, Coimbra, Portugal
| | - Max Kolton
- French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sde Boker Campus, 8499000, Midreshet Ben-Gurion, Israel
| | - Amit Kishore Singh
- Department of Botany, Bhagalpur National College (A constituent unit of Tilka Manjhi Bhagalpur University), Bhagalpur, 812007, Bihar, India.
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Keeler AM, Rafferty NE. Legume germination is delayed in dry soils and in sterile soils devoid of microbial mutualists: Species-specific implications for upward range expansions. Ecol Evol 2022; 12:e9186. [PMID: 36016820 PMCID: PMC9398887 DOI: 10.1002/ece3.9186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/27/2022] [Accepted: 07/15/2022] [Indexed: 11/14/2022] Open
Abstract
Climate change is affecting species and their mutualists and can lead to the weakening or loss of important interspecific interactions. Through independent shifts in partner phenology and distribution, climatic stress can separate mutualists temporally or spatially, leading to alterations in partner functional traits and fitness. Here, we explored the effects of the loss of microbial mutualists on legume germination success and phenology. In particular, we assessed the effects of mutualism loss via soil sterilization, increased drought, and introduction to novel soils found beyond the current distributions of two focal legume species in subalpine environments. Through common garden experiments in controlled environments, we found evidence that soil sterilization (and consequent microbial absence) and dry soils caused species-specific phenological delays of 2-5 weeks in germination, likely as a result of interaction loss between legumes and specialized germination-promoting soil microbes, such as mutualistic rhizobia. Delays in germination caused by a mismatch between legumes and beneficial microbes could negatively affect legume fitness through increased plant-plant competition later in the season. Additionally, we found evidence of the presence of beneficial microbes beyond the current elevational range of one of our focal legumes, which may allow for expansion of the leading edge, although harsh abiotic factors in the alpine may hinder this. Alterations in the strength of soil microbe-legume mutualisms may lead to reduced fitness and altered demography for both soil microbes and legumes.
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Affiliation(s)
- Andrea M. Keeler
- Department of Evolution, Ecology, and Organismal BiologyUniversity of California, RiversideRiversideCaliforniaUSA
- Rocky Mountain Biological LaboratoryCrested ButteColoradoUSA
| | - Nicole E. Rafferty
- Department of Evolution, Ecology, and Organismal BiologyUniversity of California, RiversideRiversideCaliforniaUSA
- Rocky Mountain Biological LaboratoryCrested ButteColoradoUSA
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Ayalew T, Yoseph T, Högy P, Cadisch G. Leaf growth, gas exchange and assimilation performance of cowpea varieties in response to Bradyrhizobium inoculation. Heliyon 2022; 8:e08746. [PMID: 35106387 PMCID: PMC8789522 DOI: 10.1016/j.heliyon.2022.e08746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/27/2021] [Accepted: 01/10/2022] [Indexed: 11/23/2022] Open
Abstract
Supplying nitrogen to crops through selecting high N fixing legumes and effective inoculant is one of the key strategies to improve crop productivity. However, studies related to the effect of Bradyrhizobial inoculation on leaf growth, its functioning in relation to photosynthesis, and transpiration efficiency (WUE) of cowpea [Vigna unguiculata (L.) Walp] varieties in the tropics were inadequate. A two-year field experiment was conducted at three sites to evaluate the effect of inoculation on leaf growth, gas exchanges and photosynthetic efficiency of cowpea varieties. The study treatments were composed of four varieties, Keti (IT99K-1122), TVU, Black eye bean, and White wonderer trailing and three levels of inoculation (non-inoculated or inoculated with Bradyrhizobium strains CP-24 or CP-37). Gas exchange was measured on live plants at 67–77 days after sowing, between 8:00 to 11:00 a.m. and 14:00 to 16:00 p.m. Leaf growth parameters (leaf number and leaf area) were measured by destructive sampling, and the yield data was determined by harvesting plants in the three central rows at physiological maturity. Variety TVU performed best in terms of leaf number, photosynthesis rate, and WUE. Whereas, Black eye bean revealed superior performances for leaf area, leaf area index, and stomatal conductance compared with the rest two varieties. The effect of inoculation was significant with 14.0, 23.8, 13.7, and 11.0% advantage in leaf area, leaf area index, net photosynthesis, and WUE, respectively. Moreover, the performance of cowpea of the 2018 cropping season showed a relative advantage over 2019 in terms of leaf number, leaf area, leaf area index, net photosynthesis, and stomatal conductance. Therefore, inoculating cowpea varieties with effective Bradyrhizobium strain can be a viable alternative to enhance growth, gas exchange, photosynthetic efficiency, and grain yield.
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Lu J, Shireen F, Cheng F, Bie Z. High relative humidity improve chilling tolerance by maintaining leaf water potential in watermelon seedlings. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 166:818-826. [PMID: 34225006 DOI: 10.1016/j.plaphy.2021.06.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/28/2021] [Accepted: 06/21/2021] [Indexed: 05/29/2023]
Abstract
Low temperature is a major environmental factor that severely impairs plant growth and productivity. Although the response to low temperature stress is well studied, the mechanisms of chilling tolerance are still not well understood. Here, we describe experiments that aimed to determine whether relative humidity (RH) contribute to chilling tolerance by regulating leaf water potential in watermelon seedlings. Plants exposed to chilling stress (10 °C/5 °C day/night) were severely wilted, and the water potential in their leaves was decreased. We found that maintaining high RH when plants were subjected to chilling-stress conditions attenuated the reduction in leaf water potential, reduced electrolyte leakage, improved the stability of photosynthesis, and alleviated chilling damage. Pretreatment with ABA increased chilling tolerance in low RH conditions but became ineffective in high RH conditions. Analysis of endogenous ABA content indicated that water potential mediated chilling tolerance was independent of ABA. Analysis of stomatal resistance indicated that the maintenance of water potential was related to stomatal resistance but that the balance between water absorption and loss is more important. In conclusion, high RH maintained leaf water potential and cell turgor, maintained better cell morphology, improved stomatal conductance and thus, ultimately improved the chilling tolerance of watermelon seedlings.
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Affiliation(s)
- Junyang Lu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Fareeha Shireen
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Fei Cheng
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Zhilong Bie
- Key Laboratory of Horticultural Plant Biology, Ministry of Education/College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
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Effects of Water Stress on Photosynthesis, Yield, and Water Use Efficiency in Winter Wheat. WATER 2020. [DOI: 10.3390/w12082127] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Drought has become one of the major constraints to agricultural development, particularly in areas that lack water. Studying the effects of different water stresses on the photosynthesis, growth, yield, water use efficiency (WUE) and irrigation water productivity (IWP) of winter wheat will provide data for the development of scientific irrigation strategies for water-saving agricultural methods. According to the size of the field water capacity, four different water stress levels were set, i.e., 30–40% (severe stress), 40–50% (moderate stress), 50–60% (mild stress) and 60–80% (well-watered) of field water capacity, controlling the amount of irrigation through an automatic irrigation system. The results showed that the seasonal changes in photosynthetic parameters, such as net photosynthetic rate (Pn), intercellular carbon concentration (Ci), stomatal conductance (Gs) and transpiration (E), significantly decreased under moderate and severe stress. As a result, the height, biomass and grain size of winter wheat decreased significantly, which led to low WUE and IWP. The Pn of the mild stress group only slightly decreased compared to that of the well-watered group, and was actually higher during the flowering and grain-filling stages, resulting in increases in dry biomass and 1000 grain weight of 2.07% and 1.95%, respectively. Higher WUE and IWP were attributed to higher yields and less water use. Thus, mild stress (60–80% field water capacity) resulted in the optimal use of water resources without a significant reduction in yield in the North China Plain (NCP). Therefore, mild stress can be considered a suitable environment for winter wheat growth in arid areas.
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