Journal of Plant Biochemistry and Biotechnology

RING finger proteins are the most abundant proteins in plants and may be essential for diverse aspects of cellular regulation in plant growth and development. Many RING finger proteins are E3 ubiquitin ligases, which play important roles in protein-protein interactions and ubiquitin-dependent protein degradation. The TaRF1 gene encodes a novel RING finger protein. In this study, we characterized the wheat (Triticum aestivum) RING finger domain as a hexapoid wheat ubiquitin ligase. To study the role of TaRF1 in wheat, we isolated TaRF1 from wheat spike cDNA. TaRF1 was 756 bp and encoded a putative 251-amino-acid with a predicted molecular mass of 28.57 kDa and isoelectric point of 5.75. A typical C3HC4-type RING finger domain was found at the C-terminal region of the TaRF1 protein. TaRF1 expression was investigated in the developmental stages and under various stresses by using reverse transcription polymerase chain reaction and was confirmed by subcellular localization of TaRF1 labeled with green fluorescent protein. Using the yeast 2-hybrid screen, we identified potential TaRF1-interacting proteins in a wheat spike library. Among the 8 clones that were identified as potential interacting partners of TaRF1 using yeast 2-hybrid screening, we found the strongest interaction between TaRF1 and the ubiquitin E2 enzyme TaUBC28 in tobacco leaves through biomolecular fluorescence complementation. The selectivity of interactions between E2 enzymes and RING E3 ligases represents a central and crucial part of the ubiquitin-conjugation pathways in organisms. These results indicate that the TaRF1 protein can interact with TaUBC28 in vitro and in vivo.

Plantlet regeneration in Celastrus paniculatus Willd (Celastraceae), an endangered medicinal plant has been achieved from cotyledonary leaf-derived callus. The cotyledonary leaves from mature embryo callused on MS medium supplemented with NAA (5 × 10-6 M) and Kinetin (5 × 10-6 M) with a doubling time of 16.2 days. Well developed multiple shoots of 5.6 cm could be obtained via organogenesis within 28 days on MS + BA (2 × 10-5 M). Altered shoot morphology occurred with the change in the concentration of auxins and cytokinins. Rooting (85%) of isolated shoots was achieved on McCown medium (WPM) containing IBA (5 × 10-6 M). Rooted plantlets were transferred in small pots containing sand, garden soil and vermiculite mix. The procedure can serve as a reliable and reproducible protocol for propagation and ex situ conservation ofthis species.

Atmospheric contamination by heavy metals/metalloids is a widespread global issue. Industrial discharges, along with agricultural and anthropogenic activities cause massive accumulation of arsenic (As) in soil and groundwater, which collectively results in increased toxicity of this metalloid in crop plants. Arsenic causes phytotoxicity by interfering with plant metabolic processes at physiological, biochemical and molecular levels, leading to reduced growth and productivity. In recent times, nanotechnology is adopted in sustainable agriculture to regulate As-stress management in different plants by the administration of nanoparticles. This review highlights the latest trends in research in the applications of different nanoparticles to restrict As-bioaccumulation, and ameliorate As-stress induced phytotoxicity in plant species. The performance of nanoparticles, constituted of metal or metal oxides, viz., zinc oxide (ZnO), silicon dioxide (SiO2), titanium dioxide (TiO2), iron oxide [magnetite (Fe3O4) and maghemite (Fe2O3)], copper oxide (CuO), manganese dioxide (MnO2) and cerium oxide (CeO2) during As-stress are mostly discussed in this review. In spite of numerous beneficial effects, a serious concern, from the ecological point of view, about nanoparticle interaction with flora and fauna, is raised. Therefore, it is vital to optimize the size and proper concentration of such nanoparticles before co-applying them during As-stress so as to derive the maximum benefit out of this technology.

Legumes develop root nodules in which bacteria fix nitrogen for plants. The phytohormones auxin and cytokinin regulate nodule organogenesis by recruiting various genes to effect symbiosis. Moreover, these genes are regulated by the action of microRNAs also. To understand the complex regulatory network involving miRNAs in response to phytohormones and rhizobial interactions in chickpea roots, a miRNA expression profiling was performed. Indole acetic acid and 6-benzylaminopurine at concentrations of 0.1, 1 and 10 µM were used for auxin and cytokinin exogenous treatment and Mesorhizobium ciceri to study rhizobial interaction with chickpea root. Expression profiling of a set of 11 miRNAs was performed. Further, the targets of the candidate miRNAs were identified, followed by functional annotation. This analysis revealed that cat-miR160, cat-miR164, cat-miR396 and cat-miR398 were responsive to auxin and cytokinin. cat-miR319 was found to be only auxin responsive and is known to regulate auxin signalling by targeting TEOSINTE BRANCHED/CYCLOIDEA/PCF (TCP) which interacts with auxin inducible genes. Further, cytokinin elicited a response at very low concentration of 0.1 µM, and most of the miRNAs investigated were responsive to cytokinin. Interactome analysis revealed that cat-miR164 and cat-miR168 work in conjunction to regulate auxin signalling. Interestingly, cat-miR169 and cat-miR482 were low expressing during auxin treatment and M. ciceri infection but their expression spiked during cytokinin treatment, indicating a cytokinin mediated mode of action. The miRNA expression profiling in response to phytohormones and rhizobia and the reported function of their target genes suggested a crosstalk among the phytohormonal responses during chickpea nodulation.

β-1,3-glucanase and chitinase activity in response to infection by Alternaria triticina in wheat was examined. Susceptible and resistant wheat genotypes showed differential response to infection, suggesting the use of these enzymes in identifying resistant wheat lines. Further, it was observed that both the enzymes showed similar pattern of induction due to inoculation indicating the probable synergistic action of β-1,3-glucanase and chitinase in combating the fungal infection.

Rubus ellipticus Smith. commonly known as ‘Yellow Himalayan raspberry’ is an important member of Rosaceae family with high medicinal importance having antioxidant and antibacterial properties. This study was done with the objective of characterizing 21 R. ellipticus collections from different regions of India, based on morphological descriptors and expressed sequence tags-simple sequence repeat (EST-SSR) markers. Broad phenotypic variability among the R. ellipticus collections was detected by using morphological descriptors. The Euclidian distance matrix discriminated two groups, based on morphological characters. A set of 68 EST-SSR markers were developed based on 7777 unigenes generated by us from ‘Kumarhatti-1’ collection of R. ellipticus using assembled pair—end sequences from Illumina NextSeq 500. The ESTs containing simple sequence repeat motifs were extracted using Microsatellite identification tool and primers were designed. Out of 68 EST-SSRs polymorphism was detected using 61 (89.7%) primer pairs, indicating high genetic variability in the R. ellipticus collections. Effective multiplex ratio, marker index and polymorphism information content were 0.43, 0.24 and 0.50, respectively. The unweighted pair group method with arithmetic mean coincided with the bootstrap analysis and two groups were formed, separating the collections Uttrakhand from the other. Morphological descriptors along with EST-SSR markers proved efficient in detecting the levels of genetic variability among the collections maintained in the field. These results can be used as an additional source of exploitation in R. ellipticus breeding programs.