Ever since mankind embraced technology, the largest number of inventions have been aimed at agricultural improvement, more than any other sectors where technology is used. Nonetheless, today we are ...struggling to meet the ever increasing hunger of a growing world population. We have almost exhausted the supply of traditional technological ammunitions in the arsenal of agricultural science. The only way forward is to embrace smart agricultural practice in a sustainable manner. Use of modern electronics and material science to increase production, without further increasing fertilizer or pesticide input, can be referred to as smart and sustainable agriculture. Scientists have made giant leaps in the field of ‘biology at nanoscale’ during the first decade of the present century. Nanoparticles and nanosensors have huge potential in agricultural advancements, if used wisely with proper caution. Nanoparticles can be used for getting higher yield and for crop protection. Nanoparticles can also aid in the rate limiting process of gene delivery during genetic improvement of crop species. Nanobiosensors can contribute to smart farming by growth monitoring, real time detection of pests, and continuous monitoring of local environment. In this review, we will update the readers with some of the advancements made in these directions during the last decade.
Canonical WNT signaling stabilizes β-catenin to determine cell fate in many processes from development onwards. One of its main roles in skeletogenesis is to antagonize the chondrogenic transcription ...factor SOX9. We here identify the SOXC proteins as potent amplifiers of this pathway. The SOXC genes, i.e., Sox4, Sox11, and Sox12, are coexpressed in skeletogenic mesenchyme, including presumptive joints and perichondrium, but not in cartilage. Their inactivation in mouse embryo limb bud caused massive cartilage fusions, as joint and perichondrium cells underwent chondrogenesis. SOXC proteins govern these cells cell autonomously. They replace SOX9 in the adenomatous polyposis coli-Axin destruction complex and therein inhibit phosphorylation of β-catenin by GSK3. This inhibition, a crucial, limiting step in canonical WNT signaling, thus becomes a constitutive event. The resulting SOXC/canonical WNT-mediated synergistic stabilization of β-catenin contributes to efficient repression of Sox9 in presumptive joint and perichondrium cells and thereby ensures proper delineation and articulation of skeletal primordia. This synergy may determine cell fate in many processes besides skeletogenesis.
Transcription factors (TFs) are thought to regulate many aspects of nodule and symbiosis development in legumes, although few TFs have been characterized functionally. Here, we describe regulator of ...symbiosome differentiation (RSD) of Medicago truncatula, a member of the Cysteine-2/Histidine-2 (C2H2) family of plant TFs that is required for normal symbiosome differentiation during nodule development. RSD is expressed in a nodule-specific manner, with maximal transcript levels in the bacterial invasion zone. A tobacco (Nicotiana tabacum) retrotransposon (Tnt1) insertion rsd mutant produced nodules that were unable to fix nitrogen and that contained incompletely differentiated symbiosomes and bacteroids. RSD protein was localized to the nucleus, consistent with a role of the protein in transcriptional regulation. RSD acted as a transcriptional repressor in a heterologous yeast assay. Transcriptome analysis of an rsd mutant identified 11 genes as potential targets of RSD repression. RSD interacted physically with the promoter of one of these genes, VAMP721a, which encodes vesicle-associated membrane protein 721a. Thus, RSD may influence symbiosome development in part by repressing transcription of VAMP721a and modifying vesicle trafficking in nodule cells. This establishes RSD as a TF implicated directly in symbiosome and bacteroid differentiation and a transcriptional regulator of secretory pathway genes in plants.
The phytohormone auxin is involved in the regulation of plant growth, nutrient acquisition, and response to environmental stimuli. Auxin response factors (ARFs) are transcription factors containing ...B3 DNA binding domain. ARFs play central role in auxin response, using Aux/IAA proteins as partners.
Arachis
is a genus within the
Dalbergioid
clade of papilionoid legumes, which out-branched from other members of papilionoids. Cultivated peanut (
Arachis hypogaea
L.) is an allotetraploid formed by hybridization of two parental genotypes
Arachis duranensis
, and
Arachis ipaensis
merely 10,000 years ago. We have made a genome-wide inventory of all the ARFs present in tetraploid
A. hypogaea,
as well as in two diploid parental genotypes. Our data show that Arachis contains more ARFs per diploid genome (around 31), compared to other legumes (around 25). We further observed few ARF-like genes which are defective in important domains. Most of the ARFs in tetraploid Arachis are redundant, representing the A and B sub-genomes. Some of the ARFs show expression bias from either A or B sub-genome, while some of the pairs are expressed from both sub-genomes. Many ARFs do not express in any of the conditions for which we have expression data. Finally, few pairs show differential spatio-temporal expression pattern from A and B sub-genomes, indicative of diversification of function. This is the first effort to list all the ARFs from an allotetraploid legume. The list of ARFs in all three species of Arachis will help the scientific community working to understand auxin regulation in crop legumes.
Legume seeds are important as protein and oil source for human diet. Understanding how their final seed size is determined is crucial to improve crop yield. In this study, we analyzed seed ...development of three accessions of the model legume, Medicago truncatula, displaying contrasted seed size. By comparing two large seed accessions to the reference accession A17, we described mechanisms associated with large seed size determination and potential factors modulating the final seed size. We observed that early events during embryogenesis had a major impact on final seed size and a delayed heart stage embryo development resulted to large seeds. We also observed that the difference in seed growth rate was mainly due to a difference in embryo cell number, implicating a role of cell division rate. Large seed accessions could be explained by an extended period of cell division due to a longer embryogenesis phase. According to our observations and recent reports, we observed that auxin (IAA) and abscisic acid (ABA) ratio could be a key determinant of cell division regulation at the end of embryogenesis. Overall, our study highlights that timing of events occurring during early seed development play decisive role for final seed size determination.
Summary
Legumes can host nitrogen‐fixing rhizobia inside root nodules. In model legumes, rhizobia enter via infection threads (ITs) and develop nodules in which the infection zone contains a mixture ...of infected and uninfected cells. Peanut (Arachis hypogaea) diversified from model legumes c. 50–55 million years ago. Rhizobia enter through ‘cracks’ to form nodules in peanut roots where cells of the infection zone are uniformly infected. Phylogenomic studies have indicated symbiosis as a labile trait in peanut. These atypical features prompted us to investigate the molecular mechanism of peanut nodule development.
Combining cell biology, genetics and genomic tools, we visualized the status of hormonal signaling in peanut nodule primordia. Moreover, we dissected the signaling modules of Nodule INception (NIN), a master regulator of both epidermal infection and cortical organogenesis.
Cytokinin signaling operates in a broad zone, from the epidermis to the pericycle inside nodule primordia, while auxin signaling is narrower and focused. Nodule INception is involved in nodule organogenesis, but not in crack entry. Nodulation Pectate Lyase, which remodels cell walls during IT formation, is not required. By contrast, Nodule enhanced Glycosyl Hydrolases (AhNGHs) are recruited for cell wall modification during crack entry.
While hormonal regulation is conserved, the function of the NIN signaling modules is diversified in peanut.
Abstract Aims In this study, the antifungal efficacy and phytotoxicity of silica coated porous zinc oxide nanoparticle (SZNP) were analyzed as this nanocomposite was observed to be a suitable ...platform for slow release fungicides and has the promise to bring down the dosage of other agrochemicals as well. Methods and results Loading and release kinetics of tricyclazole, a potent fungicide, were analyzed by measuring surface area (SBET) using Brunauer–Emmett–Teller (BET) isotherm and liquid chromatography tandem mass spectrometry (LC-MS/MS), respectively. The antifungal efficacy of ZnO nanoparticle (ZNP) and SZNP was investigated on two phytopathogenic fungi (Alternaria solani and Aspergillus niger). The morphological changes to the fungal structure due to ZNP and SZNP treatment were studied by field emission-scanning electron microscopy. Nanoparticle mediated elevation of reactive oxygen species (ROS) in fungal samples was detected by analyzing the levels of superoxide dismutase, catalase, thiol content, lipid peroxidation, and by 2,7-dichlorofluorescin diacetate assay. The phytotoxicity of these two nanostructures was assessed in rice plants by measuring primary plant growth parameters. Further, the translocation of the nanocomposite in the same plant model system was examined by checking the presence of fluorescein isothiocyanate tagged SZNP within the plant tissue. Conclusions ZNP had superior antifungal efficacy than SZNP and caused the generation of more ROS in the fungal samples. Even then, SZNP was preferred as an agrochemical delivery vehicle because, unlike ZNP alone, it was not toxic to plant system. Moreover, as silica in nanoform is entomotoxic in nature and nano ZnO has antifungal property, both the cargo (agrochemical) and the carrier system (silica coated porous nano zinc oxide) will have a synergistic effect in crop protection.
The lysis-lysogeny decision in the temperate coliphage λ is influenced by a number of phage proteins (CII and CIII) as well as host factors, viz. Escherichia coli HflB, HflKC and HflD. Prominent ...among these are the transcription factor CII and HflB, an ATP-dependent protease that degrades CII. Stabilization of CII promotes lysogeny, while its destabilization induces the lytic mode of development. All other factors that influence the lytic/lysogenic decision are known to act by their effects on the stability of CII. Deletion of hflKC has no effect on the stability of CII. However, when λ infects ΔhflKC cells, turbid plaques are produced, indicating stabilization of CII under these conditions.
We find that CII is stabilized in ΔhflKC cells even without infection by λ, if CIII is present. Nevertheless, we also obtained turbid plaques when a ΔhflKC host was infected by a cIII-defective phage (λcIII67). This observation raises a fundamental question: does lysogeny necessarily correlate with the stabilization of CII? Our experiments indicate that CII is indeed stabilized under these conditions, implying that stabilization of CII is possible in ΔhflKC cells even in the absence of CIII, leading to lysogeny.
We propose that a yet unidentified CII-stabilizing factor in λ may influence the lysis-lysogeny decision in ΔhflKC cells.
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