Eye lens ␣-crystallin is a member of the small heat shock protein (sHSP) family and forms large multimeric structures. Earlier studies have shown that it can act like a molecular chaperone and form a stable complex with partially unfolded proteins. We have observed that prior binding of the hydrophobic protein melittin to ␣-crystallin diminishes its chaperone-like activity toward denaturing alcohol dehydrogenase, suggesting the presence of mutually exclusive sites for these proteins in ␣-crystallin. To investigate the mechanism of the interaction between ␣-crystallin and substrate proteins, we determined the melittin-binding sites in ␣-crystallin by cross-linking studies. Localization of melittin-binding sites in ␣-crystallin resulted in the identification of RTLGPFYPSR and FVIFLDVKHFSPEDLTVK of ␣A-crystallin and FSVNLDVK of ␣B-crystallin as the chaperone sites. Of these sites, FVIFLDVKHFSPEDLTVK and FSVNLDVK were identified earlier as 1,1-bi(4-anilino) naphthalene-5,5-disulfonic acid (bis-ANS)-binding hydrophobic sites. Here we also report the synthesis and characterization of the peptide, KFVIFLDVKHFSPED-LTVK, having the melittin as well as bis-ANS-binding sequence of ␣A-crystallin. We show that this peptide has characteristics similar to that of ␣A-crystallin by in vitro thermal aggregation assay, gel filtration study, CD spectroscopy, and bis-ANS interaction studies. The peptide sequence corresponds to the ␤3 and ␤4 region present in the ␣-crystallin domain of sHSP 16.5. We hypothesize that the ␣-crystallin domain in other sHSPs may have a similar function and would likely possess the anti-aggregation property even when separated from the native protein.

In plants, auxin functions as a master controller of development, pattern formation, morphogenesis, and tropic responses. A sophisticated transport system has evolved to allow the establishment of precise spatiotemporal auxin gradients that regulate specific developmental programs. A critical unresolved question relates to how these gradients can be maintained in the presence of open plasmodesmata that allow for symplasmic exchange of essential nutrients and signaling macromolecules. Here we addressed this conundrum using genetic, physiological, and cell biological approaches and identified the operation of an auxin-GSL8 feedback circuit that regulates the level of plasmodesmal-localized callose in order to locally downregulate symplasmic permeability during hypocotyl tropic response. This system likely involves a plasmodesmal switch that would prevent the dissipation of a forming gradient by auxin diffusion through the symplasm. This regulatory system may represent a mechanism by which auxin could also regulate symplasmic delivery of a wide range of signaling agents.

In plants, communication and molecular exchanges between different cells and tissues are dependent on the apoplastic and symplastic pathways. Symplastic molecular exchanges take place through the plasmodesmata, which connect the cytoplasm of neighboring cells in a highly controlled manner. Callose, a β-1,3-glucan polysaccharide, is a plasmodesmal marker molecule that is deposited in cell walls near the neck zone of plasmodesmata and controls their permeability. During cell differentiation and plant development, and in response to diverse stresses, the level of callose in plasmodesmata is highly regulated by two antagonistic enzymes, callose synthase or glucan synthase-like and β-1,3-glucanase. The diverse modes of regulation by callose synthase and β-1,3-glucanase have been uncovered in the past decades through biochemical, molecular, genetic, and omics methods. This review highlights recent findings regarding the function of plasmodesmal callose and the molecular players involved in callose metabolism, and provides new insight into the mechanisms maintaining plasmodesmal callose homeostasis.

Cytokinins play a significant role in determining grain yield in plants. Cytokinin oxidases catalyse irreversible degradation of cytokinins and hence modulate cellular cytokinin levels. Here, we studied the role of an inflorescence meristem-specific rice cytokinin oxidase - OsCKX2 - in reducing yield penalty under salinity stress conditions. We utilized an RNAi-based approach to study the function of OsCKX2 in maintaining grain yield under salinity stress condition. Ultra-performance liquid chromatography-based estimation revealed a significant increase in cytokinins in the inflorescence meristem of OsCKX2-knockdown plants. To determine if there exists a correlation between OsCKX2 levels and yield under salinity stress condition, we assessed the growth, physiology and grain yield of OsCKX2-knockdown plants vis-à-vis the wild type. OsCKX2-knockdown plants showed better vegetative growth, higher relative water content and photosynthetic efficiency and reduced electrolyte leakage as compared with the wild type under salinity stress. Importantly, we found a negative correlation between OsCKX2 expression and plant productivity as evident by assessment of agronomical parameters such as panicle branching, filled grains per plant and harvest index both under control and salinity stress conditions. These results suggest that OsCKX2, via controlling cytokinin levels, regulates floral primordial activity modulating rice grain yield under normal as well as abiotic stress conditions.

We have recently identified and classified a cystathionine β-synthase domain containing protein family in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa L.). Based on the microarray and MPSS data, we have suggested their involvement in stress tolerance. In this study, we have characterized a rice protein of unknown function, OsCBSX4. This gene was found to be upregulated under high salinity, heavy metal, and oxidative stresses at seedling stage. Transgenic tobacco plants overexpressing OsCBSX4 exhibited improved tolerance toward salinity, heavy metal, and oxidative stress. This enhanced stress tolerance in transgenic plants could directly be correlated with higher accumulation of OsCBSX4 protein. Transgenic plants could grow and set seeds under continuous presence of 150 mM NaCl. The total seed yield in WT plants was reduced by 80%, while in transgenic plants, it was reduced only by 15-17%. The transgenic plants accumulated less Na+, especially in seeds and maintained higher net photosynthesis rate and Fv/Fm than WT plants under NaCl stress. Transgenic seedlings also accumulated significantly less H2O2 as compared to WT under salinity, heavy metal, and oxidative stress. OsCBSX4 overexpressing transgenic plants exhibit higher abiotic stress tolerance than WT plants suggesting its role in abiotic stress tolerance in plants.

Wafer-level three-dimensional integration ͑3D͒ is an emerging technology to increase the performance and functionality of integrated circuits ͑ICs͒, with adhesive wafer bonding a key step in one of the attractive technology platforms. In such an application, the dielectric adhesive layer needs to be very uniform, and precise wafer-to-wafer alignment accuracy ͑ϳ1 m͒ of the bonded wafers is required. In this paper we present a new adhesive wafer bonding process that involves partially curing ͑cross-linking͒ of the benzocyclobutene ͑BCB͒ coatings prior to bonding. The partially cured BCB layer essentially does not reflow during bonding, minimizing the impact of inhomogeneities in BCB reflow under compression and/or any shear forces at the bonding interface. The resultant nonuniformity of the BCB layer thickness after wafer bonding is less than 1% of the average layer thickness, and the wafers shift relative to each other during the wafer bonding process less than 1 m ͑average͒ for 200 mm diameter wafers. When bonding two silicon wafers using partially cured BCB, the critical adhesion energy is sufficiently high ͑ജ14 J/m 2 ͒ for subsequent IC processing.

BackgroundThe Na+/Ca2+ Exchanger (NCX) protein family is a member of the Cation/Ca2+ exchanger superfamily and its members play important roles in cellular Ca2+ homeostasis. While the functions of NCX family of proteins is well understood in humans, not much is known about the total complement of Na+/Ca2+ exchangers in plants and their role in various physiological and developmental processes. In the present study, we have identified all the NCX proteins encoded in the genomes of rice and Arabidopsis and studied their phylogeny, domain architecture and expression profiles across different tissues, at various developmental stages and under stress conditions.ResultsThrough whole genome investigation, we identified twenty-two NCX proteins encoded by fifteen genes in rice and sixteen NCX proteins encoded by thirteen genes in Arabidopsis. Based on phylogenetic reconstruction, these could be classified into five clades, members of most of which were found to possess distinct domain architecture. Expression profiling of the identified NCX genes using publicly available MPSS and microarray data showed differential expression patterns under abiotic stresses, and at various development stages. In rice, OsNCX1, OsNCX8, OsNCX9 and OsNCX15 were found to be highly expressed in all the plant parts and various developmental stages. qRT-PCR based expression analysis revealed that OsNCX3, OsNCX10 and OsNCX15 were highly induced by salt and dehydration stress. Besides, expression profiling showed differential regulation of rice NCX genes in response to calcium and EGTA. Interestingly, expression of none of the NCX genes was found to be co-regulated by NaCl and calcium.ConclusionsTogether, our results present insights into the potential role of NCX family of proteins in abiotic stresses and development. Findings of the present investigation should serve as a starting point for future studies aiming functional characterization of plant NCX family proteins.Electronic supplementary materialThe online version of this article (doi:10.1186/s12284-015-0054-5) contains supplementary material, which is available to authorized users.

The Korean black raspberry (Rubus coreanus Miquel, KB) on ripening is usually consumed as fresh fruit, whereas the unripe KB has been widely used as a source of traditional herbal medicine. Such a stage specific utilization of KB has been assumed due to the changing metabolite profile during fruit ripening process, but so far molecular and biochemical changes during its fruit maturation are poorly understood. To analyze biochemical changes during fruit ripening process at molecular level, firstly, we have sequenced, assembled, and annotated the transcriptome of KB fruits. Over 4.86 Gb of normalized cDNA prepared from fruits was sequenced using Illumina HiSeq™ 2000, and assembled into 43,723 unigenes. Secondly, we have reported that alterations in anthocyanins and proanthocyanidins are the major factors facilitating variations in these stages of fruits. In addition, up-regulation of F3′H1, DFR4 and LDOX1 resulted in the accumulation of cyanidin derivatives during the ripening process of KB, indicating the positive relationship between the expression of anthocyanin biosynthetic genes and the anthocyanin accumulation. Furthermore, the ability of RcMCHI2 (R. coreanus Miquel chalcone flavanone isomerase 2) gene to complement Arabidopsis transparent testa 5 mutant supported the feasibility of our transcriptome library to provide the gene resources for improving plant nutrition and pigmentation. Taken together, these datasets obtained from transcriptome library and metabolic profiling would be helpful to define the gene-metabolite relationships in this non-model plant.