scholarly journals Calcineurin B-Like Proteins CBL4 and CBL10 Mediate Two Independent Salt Tolerance Pathways in Arabidopsis

2019 ◽  
Vol 20 (10) ◽  
pp. 2421 ◽  
Author(s):  
Yang Yang ◽  
Chi Zhang ◽  
Ren-Jie Tang ◽  
Hai-Xia Xu ◽  
Wen-Zhi Lan ◽  
...  

In Arabidopsis, the salt overly sensitive (SOS) pathway, consisting of calcineurin B-like protein 4 (CBL4/SOS3), CBL-interacting protein kinase 24 (CIPK24/SOS2) and SOS1, has been well defined as a crucial mechanism to control cellular ion homoeostasis by extruding Na+ to the extracellular space, thus conferring salt tolerance in plants. CBL10 also plays a critical role in salt tolerance possibly by the activation of Na+ compartmentation into the vacuole. However, the functional relationship of the SOS and CBL10-regulated processes remains unclear. Here, we analyzed the genetic interaction between CBL4 and CBL10 and found that the cbl4 cbl10 double mutant was dramatically more sensitive to salt as compared to the cbl4 and cbl10 single mutants, suggesting that CBL4 and CBL10 each directs a different salt-tolerance pathway. Furthermore, the cbl4 cbl10 and cipk24 cbl10 double mutants were more sensitive than the cipk24 single mutant, suggesting that CBL10 directs a process involving CIPK24 and other partners different from the SOS pathway. Although the cbl4 cbl10, cipk24 cbl10, and sos1 cbl10 double mutants showed comparable salt-sensitive phenotype to sos1 at the whole plant level, they all accumulated much lower Na+ as compared to sos1 under high salt conditions, suggesting that CBL10 regulates additional unknown transport processes that play distinct roles from the SOS1 in Na+ homeostasis.

2020 ◽  
Vol 41 (01) ◽  
Author(s):  
P. K. Nimbolkar ◽  
Jyoti Bajeli ◽  
Arunima Tripathi ◽  
A. K. Chaube

Salinity in soil and water is a critical factor that is causing hindrance in crop production under salt affected areas. Plant metabolic activities are apparently restricted due to accumulation of salt. The event of salt stress happens to be the reason of severe alteration in the sequence of plant growth and development which ultimately reduces the survivability of plants. The physiological and biochemical mechanisms of tolerance to various osmotic and ionic components of salinity stress are evaluated at the cellular, organ and whole plant level. The course of adaptation towards salinity stress could be of various types such as avoidance, exclusion, extrusion, ion compartmentalization etc. Appropriate understanding of mechanism involved in salt tolerance at different levels in plant tissues provide a new opportunity to integrate physiological and biochemical knowledge to improve the salinity tolerance of fruit crops, especially from the nutritional aspect. Such information not only helpful in escalating the productivity in salt affected areas, but also facilitate in bringing relatively more salt affected areas under cultivation.


Author(s):  
Anthony R. Yeo ◽  
Mikiko L. Koyama ◽  
Sudhakar Chinta ◽  
Timothy J. Flowers

2015 ◽  
Vol 42 (6) ◽  
pp. 579 ◽  
Author(s):  
Martijn Slot ◽  
Kaoru Kitajima

Plant respiration plays a critical role in the C balance of plants. Respiration is highly temperature sensitive and small temperature-induced increases in whole-plant respiration could change the C balance of plants that operate close to their light-compensation points from positive to negative. Nonstructural carbohydrates are thought to play an important role in controlling respiration and its temperature sensitivity, but this role has not been studied at the whole-plant level. We measured respiration of whole Ardisia crenata Sims. seedlings and tested the hypothesis that darkness-induced C starvation would decrease the temperature sensitivity of whole-plant respiration. Compared with control plants, sugar and starch concentrations in darkened plants declined over time in all organs. Similarly, whole-plant respiration decreased. However, the temperature sensitivity of whole-plant respiration, expressed as the proportional increase in respiration per 10°C warming (Q10), increased with progressive C starvation. We hypothesise that growth respiration was suppressed in darkened plants and that whole-plant respiration represented maintenance respiration almost exclusively, which is more temperature sensitive. Alternatively, changes in the respiratory substrate during C starvation or increased involvement of alternative oxidase pathway respiration may explain the increase in Q10. Carbohydrates are important for respiration but it appears that even in C-starved A. crenata plants, carbohydrate availability does not limit respiration during short-term warming.


Author(s):  
Pavli OI ◽  
◽  
Kempapidis K ◽  
Maggioros L ◽  
Foti C ◽  
...  

Salinity is one of the most detrimental abiotic stresses leading to considerable yield and economic losses worldwide. Lettuce is a relatively salt sensitive species, thus placing the interest in the release of salt-tolerant cultivars to enhance production in saline soils. This study aimed at investigating the response of lettuce germplasm to salt stress at the germination and at the whole plant level and to examine possibilities of early selection for salt tolerant genotypes. Fifteen lettuce commercial varieties were initially screened for salt tolerance on the basis of seed germination and seedling growth potential under salt stress conditions (0, 50, 100, 150 mM NaCl). The in vitro evaluation revealed the existence of considerable genetic variation related to salt tolerance at germination and allowed for the classification of genotypes into tolerant, moderately tolerant and sensitive to salt stress. Based on this classification, six cultivars were assessed at the whole plant level using plant height, chlorophyll content and fresh and dry biomass weight as evaluation criteria. Overall findings point to the existence of a satisfactory association of genotype performance between germination and later growth stages, thus suggesting the feasibility of screening for salt tolerance at early growth stages. This approach may considerably upgrade the efficiency of selecting suitable germplasm material for cultivation in saline soils or introgression into relevant breeding programs.


Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2173
Author(s):  
Joo Hyuk Cho ◽  
Sung-Chur Sim ◽  
Kyung-Nam Kim

Soil salinity is one of the major environmental stresses that restrict the growth and development of tomato (Solanum lycopersicum L.) worldwide. In Arabidopsis, the calcium signaling pathway mediated by calcineurin B-like protein 4 (CBL4) and CBL-interacting protein kinase 24 (CIPK24) plays a critical role in salt stress response. In this study, we identified and isolated two tomato genes similar to the Arabidopsis genes, designated as SlCBL4 and SlCIPK24, respectively. Bimolecular fluorescence complementation (BiFC) and pull-down assays indicated that SlCBL4 can physically interact with SlCIPK24 at the plasma membrane of plant cells in a Ca2+-dependent manner. Overexpression of SlCBL4 or superactive SlCIPK24 mutant (SlCIPK24M) conferred salt tolerance to transgenic tomato (cv. Moneymaker) plants. In particular, the SlCIPK24M-overexpression lines displayed dramatically enhanced tolerance to high salinity. It is notable that the transgenic plants retained higher contents of Na+ and K+ in the roots compared to the wild-type tomato under salt stress. Taken together, our findings clearly suggest that SlCBL4 and SlCIPK24 are functional orthologs of the Arabidopsis counterpart genes, which can be used or engineered to produce salt-tolerant tomato plants.


Genetics ◽  
2003 ◽  
Vol 165 (1) ◽  
pp. 159-169
Author(s):  
Benjamin Boettner ◽  
Phoebe Harjes ◽  
Satoshi Ishimaru ◽  
Michael Heke ◽  
Hong Qing Fan ◽  
...  

Abstract Rap1 belongs to the highly conserved Ras subfamily of small GTPases. In Drosophila, Rap1 plays a critical role in many different morphogenetic processes, but the molecular mechanisms executing its function are unknown. Here, we demonstrate that Canoe (Cno), the Drosophila homolog of mammalian junctional protein AF-6, acts as an effector of Rap1 in vivo. Cno binds to the activated form of Rap1 in a yeast two-hybrid assay, the two molecules colocalize to the adherens junction, and they display very similar phenotypes in embryonic dorsal closure (DC), a process that relies on the elongation and migration of epithelial cell sheets. Genetic interaction experiments show that Rap1 and Cno act in the same molecular pathway during DC and that the function of both molecules in DC depends on their ability to interact. We further show that Rap1 acts upstream of Cno, but that Rap1, unlike Cno, is not involved in the stimulation of JNK pathway activity, indicating that Cno has both a Rap1-dependent and a Rap1-independent function in the DC process.


2005 ◽  
Vol 288 (5) ◽  
pp. R1396-R1410 ◽  
Author(s):  
Shaun W. Phillips ◽  
Gerard L. Gebber ◽  
Susan M. Barman

We used spectral analysis and event-triggered averaging to determine the effects of chemical inactivation of the medullary lateral tegmental field (LTF) on 1) the relationship of intratracheal pressure (ITP, an index of vagal lung inflation afferent activity) to sympathetic nerve discharge (SND) and phrenic nerve activity (PNA) and 2) central respiratory rate in paralyzed, artificially ventilated dial-urethane-anesthetized cats. ITP-SND coherence value at the frequency of artificial ventilation was significantly ( P < 0.05; n = 18) reduced from 0.73 ± 0.04 (mean ± SE) to 0.24 ± 0.04 after bilateral microinjection of muscimol into the LTF. Central respiratory rate was unexpectedly increased in 12 of these experiments (0.28 ± 0.03 vs. 0.95 ± 0.25 Hz). The ITP-PNA coherence value was variably affected by chemical inactivation of the LTF. It was unchanged when central respiratory rate was also not altered, decreased when respiratory rate was increased above the rate of artificial ventilation, and increased when respiratory rate was raised from a value below the rate of artificial ventilation to the same frequency as the ventilator. Chemical inactivation of the LTF increased central respiratory rate in four of six vagotomized cats but did not significantly affect the PNA-SND coherence value. These data demonstrate that the LTF 1) plays a critical role in mediating the effects of vagal lung inflation afferents on SND but not PNA, 2) helps maintain central respiratory rate in the physiological range, but 3) is not involved in the coupling of central respiratory and sympathetic circuits.


2021 ◽  
pp. 252-268
Author(s):  
V. V. Dyachkov ◽  

The paper deals with the grammaticalization problems in Tomo Kan (Dogon family, Niger-Congo) and, in particular, with the diachronic relationship of polypredicative constructions and TAM markers. Dogon languages are characterized by TAM systems that seem to be dia-chronically unstable since markers with a similar range of meanings go back to different lexi-cal sources in different languages of the family. TAM markers are apparently associated with polypredicative constructions, which are very common in Dogon and preserve some of their morphosyntactic properties. At the same time, Dogon languages are characterized by complex tonal changes triggered not only by phonological context but also by the syntactic position of constituents. These tonal changes, frequently referred to as tonosyntax, accompany the formation of polypredicative constructions and other syntactic phenomena. A thorough inves-tigation of Tomo Kan TAM markers shows their tonosyntactic properties to resemble those of polypredicative constructions. Moreover, assuming that tonosyntax of polypredicative con-structions triggers certain tonal contour overlays, one can account for tonal alternations ob-served in TAM forms which would have been left otherwise unexplained. However, the anal-ysis also reveals that at least two classes of TAM forms must be distinguished in Tomo Kan: one of them inherits the tonosyntax of polypredicative constructions while the other does not. A hypothesis is put forward that the latter class has a different source of grammaticalization and is probably associated with verb stem incorporation rather than with polypredication. Methodologically, the paper shows a critical role of tonology in the analysis of grammaticalization processes in tonal languages.


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