scholarly journals Elucidating the Possible Involvement of Maize Aquaporins and Arbuscular Mycorrhizal Symbiosis in the Plant Ammonium and Urea Transport under Drought Stress Conditions

Plants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 148 ◽  
Author(s):  
Gabriela Quiroga ◽  
Gorka Erice ◽  
Ricardo Aroca ◽  
Antonio Delgado-Huertas ◽  
Juan Manuel Ruiz-Lozano

This study investigates the possible involvement of maize aquaporins which are regulated by arbuscular mycorrhizae (AM) in the transport in planta of ammonium and/or urea under well-watered and drought stress conditions. The study also aims to better understand the implication of the AM symbiosis in the uptake of urea and ammonium and its effect on plant physiology and performance under drought stress conditions. AM and non-AM maize plants were cultivated under three levels of urea or ammonium fertilization (0, 3 µM or 10 mM) and subjected or not to drought stress. Plant aquaporins and physiological responses to these treatments were analyzed. AM increased plant biomass in absence of N fertilization or under low urea/ ammonium fertilization, but no effect of the AM symbiosis was observed under high N supply. This effect was associated with reduced oxidative damage to lipids and increased N accumulation in plant tissues. High N fertilization with either ammonium or urea enhanced net photosynthesis (AN) and stomatal conductance (gs) in plants maintained under well-watered conditions, but 14 days after drought stress imposition these parameters declined in AM plants fertilized with high N doses. The aquaporin ZmTIP1;1 was up-regulated by both urea and ammonium and could be transporting these two N forms in planta. The differential regulation of ZmTIP4;1 and ZmPIP2;4 with urea fertilization and of ZmPIP2;4 with NH4+ supply suggests that these two aquaporins may also play a role in N mobilization in planta. At the same time, these aquaporins were also differentially regulated by the AM symbiosis, suggesting a possible role in the AM-mediated plant N homeostasis that deserves future studies.

2014 ◽  
Vol 27 (4) ◽  
pp. 349-363 ◽  
Author(s):  
Gloria Bárzana ◽  
Ricardo Aroca ◽  
Gerd Patrick Bienert ◽  
François Chaumont ◽  
Juan Manuel Ruiz-Lozano

The relationship between modulation by arbuscular mycorrhizae (AM) of aquaporin expression in the host plant and changes in root hydraulic conductance, plant water status, and performance under stressful conditions is not well known. This investigation aimed to elucidate how the AM symbiosis modulates the expression of the whole set of aquaporin genes in maize plants under different growing and drought stress conditions, as well as to characterize some of these aquaporins in order to shed further light on the molecules that may be involved in the mycorrhizal responses to drought. The AM symbiosis regulated a wide number of aquaporins in the host plant, comprising members of the different aquaporin subfamilies. The regulation of these genes depends on the watering conditions and the severity of the drought stress imposed. Some of these aquaporins can transport water and also other molecules which are of physiological importance for plant performance. AM plants grew and developed better than non-AM plants under the different conditions assayed. Thus, for the first time, this study relates the well-known better performance of AM plants under drought stress to not only the water movement in their tissues but also the mobilization of N compounds, glycerol, signaling molecules, or metalloids with a role in abiotic stress tolerance. Future studies should elucidate the specific function of each aquaporin isoform regulated by the AM symbiosis in order to shed further light on how the symbiosis alters the plant fitness under stressful conditions.


2012 ◽  
Vol 109 (5) ◽  
pp. 1009-1017 ◽  
Author(s):  
Gloria Bárzana ◽  
Ricardo Aroca ◽  
José Antonio Paz ◽  
François Chaumont ◽  
Mari Carmen Martinez-Ballesta ◽  
...  

2011 ◽  
Vol 57 (No. 12) ◽  
pp. 541-546 ◽  
Author(s):  
G. Qiao ◽  
X.P. Wen ◽  
L.F. Yu ◽  
X.B. Ji

  Pigeon pea (Cajanus cajan) has been rapidly grown in the drought-striken Karst regions of southwest China. Present research aimed to investigate the effects of arbuscular mycorrhizae (AM) on the drought tolerance of pigeon pea, as well as to elucidate the physiological responses of AM-colonized seedlings to the water deficit. As subjected to drought stress, AM symbiosis (AMD) highly led to the positive effects on root system, plant height and stem diameter. AMD demonstrated a remarkably higher chlorophyll content, photosynthetic rate and stomatal conductance. The soluble sugar in AMD was significantly higher than that of the non-AM seedlings (NAMD), indicating the enhanced tolerance at least partially correlated with osmotic solute. Conversely, the proline (Pro) of AMD was lower, revealing the excessive Pro was not imperative for drought tolerance. After 30 days drought stress, AMD gave around a third less lipid peroxides than that of NAMD. Rather, the root activities of AMD were significantly higher than that of the latter after 10 days drought stress. Thereby, AM fungi might substantially elevate the tolerance to drought of pigeon pea, and the cumulative effects contributed to the enhanced tolerance. To date, this has been the first report concerning the enhancement of drought tolerance via AM colonization in this legume species.  


2020 ◽  
Vol 21 (5) ◽  
pp. 1748
Author(s):  
Gabriela Quiroga ◽  
Gorka Erice ◽  
Ricardo Aroca ◽  
Juan Manuel Ruiz-Lozano

Boron (B) is an essential micronutrient for higher plants, having structural roles in primary cell walls, but also other functions in cell division, membrane integrity, pollen germination or metabolism. Both high and low B levels negatively impact crop performance. Thus, plants need to maintain B concentration in their tissues within a narrow range by regulating transport processes. Both active transport and protein-facilitated diffusion through aquaporins have been demonstrated. This study aimed at elucidating the possible involvement of some plant aquaporins, which can potentially transport B and are regulated by the arbuscular mycorrhizal (AM) symbiosis in the plant B homeostasis. Thus, AM and non-AM plants were cultivated under 0, 25 or 100 μM B in the growing medium and subjected or not subjected to drought stress. The accumulation of B in plant tissues and the regulation of plant aquaporins and other B transporters were analyzed. The benefits of AM inoculation on plant growth (especially under drought stress) were similar under the three B concentrations assayed. The tissue B accumulation increased with B availability in the growing medium, especially under drought stress conditions. Several maize aquaporins were regulated under low or high B concentrations, mainly in non-AM plants. However, the general down-regulation of aquaporins and B transporters in AM plants suggests that, when the mycorrhizal fungus is present, other mechanisms contribute to B homeostasis, probably related to the enhancement of water transport, which would concomitantly increase the passive transport of this micronutrient.


Plants ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1756
Author(s):  
Neila Abdi ◽  
Angeline van Biljon ◽  
Chrisna Steyn ◽  
Maryke Tine Labuschagne

Abiotic constraints such as water deficit reduce cereal production. Plants have different strategies against these stresses to improve plant growth, physiological metabolism and crop production. For example, arbuscular mycorrhiza (AM)—bread wheat association has been shown to improve tolerance to drought stress conditions. The objective of this study was to determine the effect of AM inoculation on plant characteristics, lipid peroxidation, solute accumulation, water deficit saturation, photosynthetic activity, total phenol secretion and enzymatic activities including peroxidise (PO) and polyphenol oxidase (PPO) in two bread wheat cultivars (PAN3497 and SST806) under well-watered and drought-stressed conditions in plants grown under greenhouse conditions, to determine whether AM can enhance drought tolerance in wheat. AM inoculation improved morphological and physiological parameters in plants under stress. The leaf number increased by 35% and 5%, tiller number by 25% and 23%, chlorophyll content by 7% and 10%, accumulation of soluble sugars by 33% and 14%, electrolyte leakage by 26% and 32%, PPO by 44% and 47% and PO by 30% and 37% respectively, in PAN3497 and SST806, respectively. However, drought stress decreased proline content by 20% and 24%, oxidative damage to lipids measured as malondialdehyde by 34% and 60%, and total phenol content by 55% and 40% respectively, in AM treated plants of PAN3497 and SST806. PAN3497 was generally more drought-sensitive than SST806. This study showed that AM can contribute to protect plants against drought stress by alleviating water deficit induced oxidative stress.


Author(s):  
Javier Puy ◽  
Carlos Perez Carmona ◽  
Inga Hiiesalu ◽  
Maarja Opik ◽  
Mari Moora ◽  
...  

Phenotypic plasticity is essential for organisms to adapt to local ecological conditions. Little is known about how mutualistic interactions, such as arbuscular mycorrhizal (AM) symbiosis, mediate plant phenotypic plasticity and to what extent this plasticity may be heritable (i.e. transgenerational effects). We tested for plant plasticity within- and across-generations in response to AM symbiosis and varying water availability in a full factorial experiment over two generations, using the perennial apomictic herb Taraxacum brevicorniculatum. We examined changes in phenotype, performance, and AM fungal colonization of the offspring throughout plant development. AM symbiosis and water availability triggered phenotypic changes during the life cycle of plants. Additionally, both triggered adaptive transgenerational effects, especially detectable during the juvenile stage. Drought stress and absence of AM fungi caused concordant plant phenotypic modifications towards a stress-coping phenotype within- and across-generations. AM fungal colonization of offspring was also affected by the parental environment. AM symbiosis can trigger transgenerational effects, including changes in functional traits related to resource-use acquisition and AM fungal colonization of the offspring, in turn affecting the biotic interaction. Thus, transgenerational effects of mycorrhizal symbiosis are not limited to plant fitness, but also improve plants ability to cope with environmental stress.


2021 ◽  
Author(s):  
Guang Zhao ◽  
Yao Chen ◽  
Yangjian Zhang ◽  
Juntao Zhu ◽  
Nan Cong ◽  
...  

Abstract Aims: Vegetation in high-altitude regions is hypothesized to be more responsive to increasing atmospheric CO2 concentrations due to low CO2 partial pressure. However, this hypothesis and the underlying mechanisms driving this response at an ecosystem scale are poorly understood. We aimed to exploring the biomass allocation and plant carbon-nitrogen relationships in response to elevated CO2 in a Tibet meadow.Methods: Here, a 5-year manipulation experiment was conducted in an alpine meadow (4585 m above sea level) to explore the responses of plant carbon (C), nitrogen (N) and biomass dynamics, as well as their allocation schemes, to elevated CO2 and N fertilization.Results: Elevated CO2 alone significantly enhanced aboveground plant biomass by 98.03 %, exhibiting a stronger CO2 fertilization effect than the global average level (20 %) for grasslands. In contrast to the belowground parts, elevated CO2 caused disproportionally aboveground tissues increment in association with C and N accumulation. These results suggest a potential C limitation for plant growth in alpine ecosystems. N fertilization alleviates the N constraints on CO2 fertilization effects, which strengthened C sequestration capacity for the aboveground plant tissues. Moreover, our results indicate a decoupling between C and N cycles in alpine ecosystems in the face of elevated CO2, especially in the N-enrichment environments.Conclusions: Overall, this study shows a high sensitivity of aboveground plant biomass and decoupled C-N relationships under elevated CO2 for high-elevation alpine ecosystems, highlighting the need to incorporate altitude effects into Earth System Models in predicting C cycle feedback to climate changes.


2013 ◽  
Vol 26 (9) ◽  
pp. 1068-1078 ◽  
Author(s):  
Alfonso Navarro-Ródenas ◽  
Gloria Bárzana ◽  
Emilio Nicolás ◽  
Andrea Carra ◽  
Andrea Schubert ◽  
...  

We have performed the isolation, functional characterization, and expression analysis of aquaporins in roots and leaves of Helianthemum almeriense, in order to evaluate their roles in tolerance to water deficit. Five cDNAs, named HaPIP1;1, HaPIP1;2, HaPIP2;1, HaPIP2;2, and HaTIP1;1, were isolated from H. almeriense. A phylogenetic analysis of deduced proteins confirmed that they belong to the water channel proteins family. The HaPIP1;1, HaPIP2;1, and HaTIP1;1 genes encode functional water channel proteins, as indicated by expression assays in Saccharomyces cerevisiae, showing divergent roles in the transport of water, CO2, and NH3. The expression patterns of the genes isolated from H. almeriense and of a previously described gene from Terfezia claveryi (TcAQP1) were analyzed in mycorrhizal and nonmycorrhizal plants cultivated under well-watered or drought-stress conditions. Some of the studied aquaporins were subjected to fine-tuned expression only under drought-stress conditions. A beneficial effect on plant physiological parameters was observed in mycorrhizal plants with respect to nonmycorrhizal ones. Moreover, stress induced a change in the mycorrhizal type formed, which was more intracellular under drought stress. The combination of a high intracellular colonization, together with the fine-tuned expression of aquaporins could result in a morphophysiological adaptation of this symbiosis to drought conditions.


Agronomy ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 523
Author(s):  
Yang Wang ◽  
Yufang Huang ◽  
Wen Fu ◽  
Wenqing Guo ◽  
Ning Ren ◽  
...  

Inadequate water and nitrogen (N) supplies can limit the productivity of maize. Climate change will likely increase drought in many regions on a global scale. The determination of N fertilizer rates under field drought conditions will be critical toward the reduction of agricultural risk. For this study, drought-resistant/sensitive cultivars were selected as experimental samples. Our results revealed that drought stress reduced the relative water content (RWC) of leaves, which resulted in leaf curling, while decreasing photosynthesis levels and N accumulation. In contrast to those without N treatments, the application of N significantly increased grain yields by 26.8% during the wet year but increased only by 5.4% during the dry year. Under the same N levels, the reduction in yield caused by drought increased with the increased application of N. This was because the application of the N fertilizer translated to increase the leaf area and transpiration, exacerbated the soil water loss and induced a leaf curling state in maize, which had deleterious effects on photosynthesis and N absorption. During the dry year, the yields of drought-sensitive cultivars were even less than those without the application of N. Compared with those of drought-sensitive cultivars, the RWCs of drought-resistant cultivars decreased more rapidly, and they entered the state of leaf curling earlier. Thus, N fertilizer inputs should be reduced, and the extent of N fertilization for drought-sensitive cultivars should be reduced even further.


2021 ◽  
Vol 108 (june) ◽  
Author(s):  
Subramanian K S ◽  
◽  
Praghadeesh M ◽  
Balakrishnan N ◽  
Rajkishore S K ◽  
...  

Mycorrhizas are known to improve host plant nutritional status as a consequence of water transport from the soil to the host plant through the external mycelium as a direct effect or improved host plant nutrition primarily, phosphorus as an indirect effect. The direct hyphal water transport is quantified to be meager and a major part of the benefits of mycorrhizal symbiosis is indirect and nutritionally related. In arid and semi-arid regions where drought occurrence is very frequent and soil moisture content is highly restricted, mycorrhizas can assist in exploiting the soil beyond the rhizosphere that helps the host plant to withstand drought stress conditions. The drought tolerance in mycorrhiza-inoculated plants is quite complex and such response is due to a series of processes such as improved nitrogen (N) availability in soils, extensive root surface area and cationic exchange capacity, collective N assimilatory pathways in plant-mycorrhizal system, luxuriant uptake of nutrients besides remobilization of nutrients to support grain growth. These physiological, biochemical, nutritional and morphological changes in the mycorrhizas associated host plants have contributed to the ability of the host plants to survive under limited water environments. Despite mycorrhiza-assisted and N nutritionally enabled host plant drought tolerance is evident, more research is required to gain insights into the mechanisms involved. This review highlights the role of mycorrhizas on N dynamics in the rhizosphere and enhanced host plant N nutrition that collectively contributes to the sustained crop productivity under drought stress conditions.


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