Ca2+ homeostasis is required to maintain a delicate balance of cytosolic Ca2+ during normal and adverse growth conditions. Various Ca2+ transporters actively participate to maintain this delicate ...balance especially during abiotic stresses and developmental events in plants. In this study, we present a genome‐wide account, detailing expression profiles, subcellular localization and functional analysis of rice Ca2+ transport elements. Exhaustive in silico data mining and analysis resulted in the identification of 81 Ca2+ transport element genes, which belong to various groups such as Ca2+‐ATPases (pumps), exchangers, channels, glutamate receptor homologs and annexins. Phylogenetic analysis revealed that different Ca2+ transporters are evolutionarily conserved across different plant species. Comprehensive expression analysis by gene chip microarray and quantitative RT‐PCR revealed that a substantial proportion of Ca2+ transporter genes were expressed differentially under abiotic stresses (salt, cold and drought) and reproductive developmental stages (panicle and seed) in rice. These findings suggest a possible role of rice Ca2+ transporters in abiotic stress and development triggered signaling pathways. Subcellular localization of Ca2+ transporters from different groups in Nicotiana benthamiana revealed their variable localization to different compartments, which could be their possible sites of action. Complementation of Ca2+ transport activity of K616 yeast mutant by Ca2+‐ATPase OsACA7 and involvement in salt tolerance verified its functional behavior. This study will encourage detailed characterization of potential candidate Ca2+ transporters for their functional role in planta.
Complete documentation of different rice calcium transporters is reported here. Regulation of different transporters at transcript level suggested their possible role in abiotic stress and development signaling. Variable sub‐cellular localization hint toward their activity at different sub‐cellular location. Complementation of mutant calcium ATPase activity and salt tolerance in yeast by OsACA7 imply its functional role in abiotic stress tolerance.
Intricate cellular and molecular events occur during plant–pathogen interactions. They cause major metabolic perturbations in the host and alterations in sugar metabolism play a pivotal role in ...governing the outcome of various kinds of plant–pathogen interactions. Sugar metabolizing enzymes and transporters of both host and pathogen origin get differentially regulated during the interactions. Both plant and pathogen compete for utilizing the host sugar metabolic machinery and in turn promote resistant or susceptible responses. However, the kind of sugar metabolism alteration that is beneficial for the host or pathogen is yet to be properly understood. Recently developed tools and methodologies are facilitating research to understand the intricate dynamics of sugar metabolism during the interactions. The present review elaborates current understanding, future challenges and ongoing quest on sugar metabolism, mobilization and regulation during various plant–pathogen interactions.
A 10-year-old male presented with sudden-onset diminution of vision in both eyes. On systemic examination, he had severe hypertension, no pulse deficit, short stature, and no other focal neurological ...deficit. Dilated fundoscopy showed bilateral grade 4 hypertensive retinopathy with macular star formation. Detailed laboratory investigations revealed a stage 5 chronic kidney disease (CKD). We present this case to highlight this rare ocular manifestation of CKD in pediatric age group.
The voltage-dependent anion channels (VDACs) are the most abundant proteins present on the outer mitochondrial membrane. They serve a myriad of functions ranging from energy and metabolite exchange ...to highly debatable roles in apoptosis. Their role in molecular transport puts them on the center stage as communicators between cytoplasmic and mitochondrial signaling events. Beyond their general role as interchangeable pores, members of this family may exhibit specific functions. Even after nearly five decades of their discovery, their role in plant systems is still a new and rapidly emerging field. The information on biochemical regulation of VDACs is limited. Various interacting proteins and post-translational modifications (PTMs) modulate VDAC functions, amongst these, phosphorylation is quite noticeable. In this review, we have tried to give a glimpse of the recent advancements in the biochemical/interactional regulation of plant VDACs. We also cover a critical analysis on the importance of PTMs in the functional regulation of VDACs. Besides, the review also encompasses numerous studies which can identify VDACs as a connecting link between Ca
and reactive oxygen species signaling in special reference to the plant systems.
Phospholipase C (PLC) is one of the major lipid hydrolysing enzymes, implicated in lipid mediated signaling. PLCs have been found to play a significant role in abiotic stress triggered signaling and ...developmental processes in various plant species. Genome wide identification and expression analysis have been carried out for this gene family in Arabidopsis, yet not much has been accomplished in crop plant rice.
An exhaustive in-silico exploration of rice genome using various online databases and tools resulted in the identification of nine PLC encoding genes. Based on sequence, motif and phylogenetic analysis rice PLC gene family could be divided into phosphatidylinositol-specific PLCs (PI-PLCs) and phosphatidylcholine- PLCs (PC-PLC or NPC) classes with four and five members, respectively. A comparative analysis revealed that PLCs are conserved in Arabidopsis (dicots) and rice (monocot) at gene structure and protein level but they might have evolved through a separate evolutionary path. Transcript profiling using gene chip microarray and quantitative RT-PCR showed that most of the PLC members expressed significantly and differentially under abiotic stresses (salt, cold and drought) and during various developmental stages with condition/stage specific and overlapping expression. This finding suggested an important role of different rice PLC members in abiotic stress triggered signaling and plant development, which was also supported by the presence of relevant cis-regulatory elements in their promoters. Sub-cellular localization of few selected PLC members in Nicotiana benthamiana and onion epidermal cells has provided a clue about their site of action and functional behaviour.
The genome wide identification, structural and expression analysis and knowledge of sub-cellular localization of PLC gene family envisage the functional characterization of these genes in crop plants in near future.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Calcium (Ca
) signaling is pivotal in transmission of information in the cell. Various Ca
sensing molecules work to sense and relay the encrypted messages to the intended targets in the cell to ...maintain this signal transduction. CBL-interacting protein kinases (CIPKs) are crucial components of Ca
signal transduction during various abiotic stresses. Although there are intron rich CIPKs in the plant genome but very little has been reported about their alternative splicing. Moreover the physiological significance of this event in the Ca
signaling is still elusive. Therefore in this study, we have selected CIPK3, which has highest number of splice variants amongst Arabidopsis CIPKs. Expression profiling of five splice variants of CIPK3 by qRT-PCR in four
ecotypes revealed preferential transcript accumulation but similar subcellular localization of the variants and interaction with similar CBLs. ABA and drought treatment resulted in the higher accumulation of the alternately spliced transcripts of
in Arabidopsis ecotype
The transcripts of
and
are relatively more induced compared to other alternative splice variants. Out of four splice variants studied, we found CIPK3.1 and CIPK3.2 showing preference for ABR1, a previously reported interactor of CIPK3. We conclude that the differential expression and choice of downstream partner by CIPK3-splice variants might be one of the mechanisms of Ca
mediated preferential regulation of ABA and other stress signals.
Voltage-dependent anion channels (VDACs) are conserved proteins of the mitochondria. We have functionally compared
VDACs using
and M3 yeast system. VDAC (1, 2, and 4) were able to restore
growth in ...elevated temperature, in oxidative and salt stresses, whereas VDAC3 only partially rescued
in these conditions. The ectopic expression of
(1, 2, 3, and 4) in mutant yeast recapitulated the mitochondrial membrane potential thus, enabled it to maintain reactive oxygen species homeostasis. Overexpression of these VDACs (
in M3 strain did not display any synergistic or antagonistic activity with the native yeast VDAC1 (ScVDAC1). Collectively, our data suggest that
VDACs are involved in regulating respiration, reactive oxygen species homeostasis, and stress tolerance in yeast.
In plant cell, cations gradient in cellular compartments is maintained by synergistic action of various exchangers, pumps and channels. The Arabidopsis exchanger family members (AtCCX3 and AtCCX5) ...were previously studied and belong to CaCA (calcium cation exchangers) superfamily while none of the rice CCXs has been functionally characterized for their cation transport activities till date. Rice genome encode four CCXs and only OsCCX2 transcript showed differential expression under abiotic stresses and Ca(2+) starvation conditions. The OsCCX2 localized to tonoplast and suppresses the Ca(2+) sensitivity of K667 (low affinity Ca(2+) uptake deficient) yeast mutant under excess CaCl2 conditions. In contrast to AtCCXs, OsCCX2 expressing K667 yeast cells show tolerance towards excess Na(+), Li(+), Fe(2+), Zn(2+) and Co(2+) and suggest its ability to transport both mono as well as divalent cations in yeast. Additionally, in contrast to previously characterized AtCCXs, OsCCX2 is unable to complement yeast trk1trk2 double mutant suggesting inability to transport K(+) in yeast system. These finding suggest that OsCCX2 having distinct metal transport properties than previously characterized plant CCXs. OsCCX2 can be used as potential candidate for enhancing the abiotic stress tolerance in plants as well as for phytoremediation of heavy metal polluted soil.
Plant nutrition is one of the important areas for improving the yield and quality in crops as well as non-crop plants. Potassium is an essential plant nutrient and is required in abundance for their ...proper growth and development. Potassium deficiency directly affects the plant growth and hence crop yield and production. Recently, potassium-dependent transcriptomic analysis has been performed in the model plant Arabidopsis, however in cereals and crop plants; such a transcriptome analysis has not been undertaken till date. In rice, the molecular mechanism for the regulation of potassium starvation responses has not been investigated in detail. Here, we present a combined physiological and whole genome transcriptomic study of rice seedlings exposed to a brief period of potassium deficiency then replenished with potassium. Our results reveal that the expressions of a diverse set of genes annotated with many distinct functions were altered under potassium deprivation. Our findings highlight altered expression patterns of potassium-responsive genes majorly involved in metabolic processes, stress responses, signaling pathways, transcriptional regulation, and transport of multiple molecules including K(+). Interestingly, several genes responsive to low-potassium conditions show a reversal in expression upon resupply of potassium. The results of this study indicate that potassium deprivation leads to activation of multiple genes and gene networks, which may be acting in concert to sense the external potassium and mediate uptake, distribution and ultimately adaptation to low potassium conditions. The interplay of both upregulated and downregulated genes globally in response to potassium deprivation determines how plants cope with the stress of nutrient deficiency at different physiological as well as developmental stages of plants.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
