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Main conclusion OsJAZ11 regulates phosphate homeostasis by suppressing jasmonic acid signaling and biosynthesis in rice roots. Abstract Jasmonic Acid (JA) is a key plant signaling molecule which negatively regulates growth processes including root elongation. JAZ (JASMONATE ZIM-DOMAIN) proteins function as transcriptional repressors of JA signaling. Therefore, targeting JA signaling by deploying JAZ repressors may enhance root length in crops. In this study, we overexpressed JAZ repressor OsJAZ11 in rice to alleviate the root growth inhibitory action of JA. OsJAZ11 is a low phosphate (Pi) responsive gene which is transcriptionally regulated by OsPHR2. We report that OsJAZ11 overexpression promoted primary and seminal root elongation which enhanced Pi foraging. Expression studies revealed that overexpression of OsJAZ11 also reduced Pi starvation response (PSR) under Pi limiting conditions. Moreover, OsJAZ11 overexpression also suppressed JA signaling and biosynthesis as compared to wild type (WT). We further demonstrated that the C-terminal region of OsJAZ11 was crucial for stimulating root elongation in overexpression lines. Rice transgenics overexpressing truncated OsJAZ11ΔC transgene (i.e., missing C-terminal region) exhibited reduced root length and Pi uptake. Interestingly, OsJAZ11 also regulates Pi homeostasis via physical interaction with a key Pi sensing protein, OsSPX1. Our study highlights the functional connections between JA and Pi signaling and reveals JAZ repressors as a promising candidate for improving low Pi tolerance of elite rice genotypes.

Present investigation demonstrated the effect of central histaminergic transmission on the compulsive-like marble burying and spontaneous alteration behavior (SAB) in mice. Result demonstrates that on enhancement of endogenous histaminergic transmission in mice achieved by central (i.c.v.) administration of histamine or central histamine neuronal releaser, H3 receptor antagonist or on intraperitoneal (i.p.) administration of histamine precursor, l-histidine significantly attenuated the number of marble buried in marble burying behavior (MBB) test as well as obliterated the persistent behavior induced by 5-HT1A receptor agonist, 8-OH-DPAT in T-Maze test. Furthermore, central injection of histamine H1 receptor agonist, FMPH or H2 receptors agonist, amthamine also attenuated the MBB in mice. On the other hand, prior i.c.v administration of H1 but not H2 receptor antagonist attenuated the effects exhibited in MBB test on mice by all the above agents capable of enhancing the endogenous central histaminergic transmission. Thus, the results of the present investigation delineate the attenuating effect of central histaminergic transmission predominantly via H1 receptor on compulsive-like behavior in mice.

Purple acid phosphatases (PAPs) play important roles in phosphate (Pi) acquisition and utilization. These PAPs hydrolyze organic Phosphorus (P) containing compounds in rhizosphere as well as inside the plant cell. However, roles of PAPs in one of the most widely cultivated legumes, chickpea (Cicer arietnum L.), have not been unraveled so far. In the present study, we identified 25 putative PAPs in chickpea (CaPAPs) which possess functional PAP motifs and domains. Differential regulation of CaPAPs under different nutrient deficiencies revealed their roles under multiple nutrient stresses including Pi deficiency. Interestingly, most of the CaPAPs were prominently expressed in flowers and young pods indicating their roles in flower and seed development. Association mapping of SNPs underlying CaPAPs with seed traits revealed significant association of low Pi inducible CaPAP7 with seed weight and phytate content. Biochemical characterization of recombinant CaPAP7 established it to be a functional acid phosphatase with highest activity on most abundant organic-P substrate, phytate. Exogenous application of recombinant CaPAP7 enhanced biomass and Pi content of Arabidopsis seedlings supplemented with phytate as sole P source. Taken together, our results uncover the PAPs in chickpea and potential roles of CaPAP7 in seed phytate accumulation.

Intrigued by the report demonstrating an increase in brain histamine levels by ethanol administration and central histamine transmission to affect the anxiety related behaviors, the present study examined the permissive role of central histaminergic transmission in the acute anxiolytic-like effect of the ethanol on elevated plus maze (EPM) in mice. Results demonstrated that prior administration of the agents that are known to enhance the brain histamine transmission, i.e. low dose of histamine (0.1μg/mouse, i.c.v.) or histamine precursor, l-histidine (500, 1000mg/kg, i.p.) or low dose of histamine releasing agent (H3 receptor inverse agonist), thioperamide (2μg/mouse) attenuated the acute anitanxiety-like effect of ethanol (2g/kg, i.p, 8% w/v) in mice on EPM. However, pre-treatment with the H1 receptor antagonist, cetirizine (0.1μg/mouse, i.c.v.) or H2 receptor antagonist, ranitidine (50μg/mouse, i.c.v.) failed to affect the attenuating effect of low dose of histamine on ethanol induced anxiolysis. On the other hand, only H1 receptor antagonist, cetirizine (0.1μg/mouse, i.c.v.) was able to partially reverse the attenuation of ethanol induced anxiolysis by l-histidine (1000mg/kg, i.p.). Surprisingly, in mice pre-treated with the higher dose of histamine (50μg/mouse, i.c.v.) or thioperamide (10μg/mouse, i.c.v.), the ethanol (2g/kg, i.p.) induced antianxiety-like effect was further enhanced on EPM. Furthermore, this potentiating effect of high dose of histamine on the ethanol (2g/kg, i.p.) was exacerbated on pre-treatment with the H1 receptor antagonist, cetirizine, while H2 receptor antagonist, ranitidine completely reversed this action of high dose of histamine on ethanol. Supportive to these results, i.c.v. pre-treatment with H1 receptor agonist, FMPH (2, 6.5μg/mouse, i.c.v.) attenuated while H2 receptor agonist, amthamine (0.1, 0.5μg/mouse, i.c.v.) enhanced the ethanol induced anxiolysis in mice. Thus, it is reasonable to contemplate that central histaminergic transmission functions to negatively modulate the acute ethanol-induced anxiolysis probably via stimulation of postsynaptic H1 receptor and histamine might contribute to the anxiolytic action of ethanol via H2 receptor activation.

Chickpea cultivation experiences huge losses due to several biotic and abiotic stresses. Deficiency of mineral nutrients such as phosphorus is a major limiting factor for chickpea production. In this chapter, we summarize our current understanding about phosphorus deficiency responses in chickpea and explore probable strategies to improve low P tolerance of chickpea. Phosphate being a key macronutrient provides the energy demand for cellular growth, patterning, differentiation and regulates the plant growth from germination to ultimate senescence. Therefore, slight variation of P status in plants switches different morphological, physiological and biochemical adaptations in chickpea to replenish the normal P status. In legumes like chickpea, seed phytate content correlates with seed size. Different approaches have targeted multifaceted roles of P nutrition in improving seed quality and size of phytate-rich chickpea seeds. Emerging evidences reveal a larger role of P levels in altering plants response to environmental stresses. We here discuss these recent advances in deciphering cross talks between phosphorus nutrition and various other stresses. We finally discuss how low P condition in plants affects other abiotic and biotic stresses to comply with the fine trade-off between plant growth and suppression of stress/defence response.

Phosphorus (P) deficiency limits plant growth and yield. Since plants can absorb only the inorganic form of P (Pi), a large portion of soil P (organic and inorganic P complexes) remains unused. Here, we identified and characterized a PHR2-regulated, novel low-Pi-responsive haloacid dehalogenase (HAD)-like hydrolase, OsHAD1. While OsHAD1 is a functional HAD protein having both acid phosphatase and phytase activities, it showed little homology with other known low-Pi-responsive HAD superfamily members. Recombinant OsHAD1 is active at acidic pH and dephosphorylates a broad range of organic and inorganic P-containing substrates, including phosphorylated serine and sodium phytate. Exogenous application of recombinant OsHAD1 protein in growth medium supplemented with phytate led to marked increases in growth and total P content of Pi-deficient wild-type rice (Oryza sativa) seedlings. Furthermore, overexpression of OsHAD1 in rice resulted in enhanced phosphatase activity, biomass, and total and soluble P contents in Pi-deficient transgenic seedlings treated with phytate as a restricted Pi source. Gene expression and metabolite profiling revealed enhanced Pi starvation responses, such as up-regulation of multiple genes involved in Pi uptake and solubilization, accumulation of organic acids, enhanced secretory phosphatase activity, and depletion of ATP in overexpression lines as compared with the wild type. To elucidate the underlying regulatory mechanisms of OsHAD1, we performed in vitro pull-down assays, which revealed the association of OsHAD1 with protein kinases such as OsNDPKs. We conclude that, besides dephosphorylation of cellular organic P, OsHAD1 in coordination with kinases may regulate the phosphorylation status of downstream targets to accomplish Pi homeostasis under limited Pi supply.

The present investigation explored the modulatory role of serotonergic transmission in the acute ethanol-induced effects on immobility time in the mouse forced swim test (FST). Acute i.p. administration of ethanol (20% w/v, 2 or 2.5 g/kg, i.p.) decreased the immobility time in FST of mice, indicating its antidepressant-like effect while lower doses of ethanol (1, 1.5 g/kg, i.p.) were devoid of any effect in the FST. The mice pre-treated with a sub-effective dose of 5-HT2A agonist, DOI (10 μg/mouse, i.c.v.) or 5-HT1A receptor antagonist, WAY 100635 (0.1 μg/mouse, i.c.v.) but not with the 5-HT2A/2C antagonist, ketanserin (1.5 μg/mouse, i.c.v.) exhibited a synergistic reduction in the immobility time induced by sub-effective dose of ethanol (1.5 g/kg, i.p.). On the other hand, ethanol (2.5 g/kg, i.p.) failed to decrease the immobility time in mice, pre-treated with 5-HT1A agonist, 8-OH-DPAT (0.1 μg/mouse, i.c.v.) or ketanserin (1.5 μg/mouse, i.c.v.). In addition, pre-treatment with a 5-HT neuronal synthesis inhibitor, p-CPA (300 mg/kg, i.p. × 3 days) attenuated the anti-immobility effect ethanol (2.5 g/kg, i.p.) in mouse FST. Thus, the results of the present study points towards the essentiality of the central 5-HT transmission at the synapse for the ethanol-induced antidepressant-like effect in the FST wherein the regulatory role of the 5-HT1A receptor or contributory role of the 5-HT2A/2C receptor-mediated mechanism is proposed in the anti-immobility effect of acute ethanol in mouse FST.