90 research outputs found
Current trends and future prospects of biotechnological interventions through tissue culture in apple
No full textApple (Malus domestica Borkh.), which is a widely cultivated, important economic fruit crop with nutritive and medicinal importance, has emerged as a model horticultural crop in this post-genomic era. Apple cultivation is heavily dependent on climatic condition and is susceptible to several diseases caused by fungi, bacteria, viruses, insects, etc. Extensive research work has been carried out to standardize tissue culture protocols and utilize them in apple improvement. We review the in vitro shoot multiplication, rooting, transformation and regeneration methodologies in apple and tabulate various such protocols for easy reference. The utility and limitation of transgenesis in apple improvement have also been summarized. The concepts of marker-free plants, use of non-antibiotic resistance selectable markers, and cisgenic and intragenic approaches are highlighted. Furthermore, the limitations, current trends and future prospects of tissue culture-mediated biotechnological interventions in apple improvement are discussed
Current trends and future prospects of biotechnological interventions through tissue culture in apple.
No full textApple (Malus domestica Borkh.), which is a
widely cultivated, important economic fruit crop with
nutritive and medicinal importance, has emerged as a
model horticultural crop in this post-genomic era. Apple
cultivation is heavily dependent on climatic condition and
is susceptible to several diseases caused by fungi, bacteria,
viruses, insects, etc. Extensive research work has been
carried out to standardize tissue culture protocols and utilize
them in apple improvement. We review the in vitro
shoot multiplication, rooting, transformation and regeneration
methodologies in apple and tabulate various such
protocols for easy reference. The utility and limitation of
transgenesis in apple improvement have also been summarized.
The concepts of marker-free plants, use of nonantibiotic
resistance selectable markers, and cisgenic and
intragenic approaches are highlighted. Furthermore, the
limitations, current trends and future prospects of tissue
culture-mediated biotechnological interventions in apple
improvement are discussed
Alterations in plant sugar metabolism: signatory of pathogen attack
No full textMain conclusion
This review summarizes the current understanding, future challenges and ongoing quest on sugar metabolic alterations that influence the outcome of plant–pathogen interactions.
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
Alterations in rice chloroplast integrity, photosynthesis and metabolome associated with pathogenesis of Rhizoctonia solani
No full textAbstractSheath blight disease is caused by a necrotrophic fungal pathogen Rhizoctonia solani and it continues to be a challenge for sustainable rice cultivation. In this study, we adopted a multi-pronged approach to understand the intricacies of rice undergoing susceptible interactions with R. solani. Extensive anatomical alteration, chloroplast localized ROS, deformed chloroplast ultrastructure along with decreased photosynthetic efficiency were observed in infected tissue. GC-MS based metabolite profiling revealed accumulation of glycolysis and TCA cycle intermediates, suggesting enhanced respiration. Several aromatic and aliphatic amino acids along with phenylpropanoid intermediates were also accumulated, suggesting induction of secondary metabolism during pathogenesis. Furthermore, alterations in carbon metabolism along with perturbation of hormonal signalling were highlighted in this study. The gene expression analysis including RNAseq profiling reinforced observed metabolic alterations in the infected tissues. In conclusion, the present study unravels key events associated during susceptible rice-R. solani interactions and identifies metabolites and transcripts that are accumulated in infected tissues.</jats:p
Fungal effectors, the double edge sword of phytopathogens
No full textPhyto-pathogenic fungi can cause huge damage to crop production. During millions of years of coexistence, fungi have evolved diverse life-style to obtain nutrients from the host and to colonize upon them. They deploy various proteinaceous as well as non-proteinaceous secreted molecules commonly referred as effectors to sabotage host machinery during the infection process. The effectors are important virulence determinants of pathogenic fungi and play important role in successful pathogenesis, predominantly by avoiding host-surveillance system. However, besides being important for pathogenesis, the fungal effectors end-up being recognized by the resistant cultivars of the host, which mount a strong immune response to ward-off pathogens. Various recent studies involving different pathosystem have revealed the virulence/avirulence functions of fungal effectors and their involvement in governing the outcome of host–pathogen interactions. However, the effectors and their cognate resistance gene in the host remain elusive for several economically important fungal pathogens. In this review, using examples from some of the biotrophic, hemi-biotrophic and necrotrophic pathogens, we elaborate the double-edged functions of fungal effectors. We emphasize that knowledge of effector functions can be helpful in effective management of fungal diseases in crop plants
Draft Genome Sequence of <i>Zhihengliuella</i> sp. Strain ISTPL4, a Psychrotolerant and Halotolerant Bacterium Isolated from Pangong Lake, India
No full textABSTRACT
Zhihengliuella
sp. strain ISTPL4, a psychrotolerant bacterium, was isolated from brackish water of the high-altitude Pangong Lake in India. In this study, we report its draft genome sequence, which contains 3,529,629 bp with a G+C content of 69.84%. The genome is enriched in genes associated with cold adaptation and plant growth promotion.
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Identification of candidate pathogenicity determinants of Rhizoctonia solani AG1-IA, which causes sheath blight disease in rice
No full textSheath blight disease is one of the predominant diseases of rice and it is caused by the necrotrophic fungal pathogen Rhizoctonia solani. The mechanistic insight about its widespread success as a broad host range pathogen is limited. In this study, we endeavor to identify pathogenicity determinants of R. solani during infection process in rice. Through RNAseq analysis, we identified a total of 65 and 232 R. solani (strain BRS1) genes to be commonly upregulated in three different rice genotypes (PB1, Tetep, and TP309) at establishment and necrotrophic phase, respectively. The induction of genes encoding extracellular protease, ABC transporter, and transcription factors were notable during establishment phase. While during necrotrophic phase, several CAZymes, sugar transporters, cellular metabolism, and protein degradation-related genes were prominently induced. We have also identified few putative secreted effector encoding genes that were upregulated during pathogenesis. The qPCR analysis further validated the phase-specific expression dynamics of some selected putative effectors and pathogenicity-associated genes. Overall, the present study reports identification of key genes and processes that might be crucial for R. solani pathogenesis. The ability to effectively damage host cell wall and survive in hostile plant environment by managing oxidative stress, cytotoxic compounds, etc. is being proposed to be important for pathogenesis of R. solani in rice. The functional characterization of these genes would provide key insights about this important pathosystem and facilitate development of strategies to control this devastating disease
Functional interplay between two Xanthomonas oryzae pv,. oryzae secretion systems in modulating virulence on rice
No full textThe type II (T2S) and type III (T3S) secretion systems are important for virulence of Xanthomonas oryzae pv. oryzae, causal agent of bacterial leaf blight of rice. The T3S of gram-negative bacterial plant pathogens has been shown to suppress host defense responses, including programmed cell death reactions, whereas the T2S is involved in secreting cell-wall-degrading enzymes. Here, we show that a T3S-deficient (T3S̅) mutant of X. oryzae pv. oryzae can induce a basal plant defense response seen as callose deposition, immunize rice against subsequent X. oryzae pv. oryzae infection, and cause cell-death-associated nuclear fragmentation. A T2S̅ T3S̅ double mutant exhibited a substantial reduction in the ability to evoke these responses. We purified two major effectors of the X. oryzae pv. oryzae T2S and characterized them to be a cellulase (ClsA) and a putative cellobiosidase (CbsA). The purified ClsA, CbsA, and lipase/esterase (LipA; a previously identified T2S effector) pro teins induced rice defense responses that were suppressible by X. oryzae pv. oryzae in a T3S-dependent manner. These defense responses also were inducible by the products of the action of these purified proteins on rice cell walls. We further show that a CbsA̅ mutant or a ClsA̅ LipA̅double mutant are severely virulence deficient. These results indicate that the X. oryzae pv. oryzae T2S secretes important virulence factors, which induce innate rice defense responses that are suppressed by T3S effectors to enable successful infection
The regulatory epicenter of miRNAs
No full textmiRNAs are small non-coding RNAs with average length of ~21 bp. miRNA formation seems to be dependent upon
multiple factors besides Drosha and Dicer, in a tissue/stage-specific manner, with interplay of several specific binding
factors. In the present study, we have investigated transcription factor binding sites in and around the genomic sequences
of precursor miRNAs and RNA-binding protein (RBP) sites in miRNA precursor sequences, analysed and tested in
comprehensive manner. Here, we report that miRNA precursor regions are positionally enriched for binding of
transcription factors as well as RBPs around the 3′ end of mature miRNA region in 5′ arm. The pattern and distribution of
such regulatory sites appears to be a characteristic of precursor miRNA sequences when compared with non-miRNA
sequences as negative dataset and tested statistically.When compared with 1 kb upstreamregions, a sudden sharp peak for
binding sites arises in the enriched zone near the mature miRNA region. An expression-data-based correlation analysis
was performed between such miRNAs and their corresponding transcription factors and RBPs for this region. Some
specific groups of binding factors and associated miRNAs were identified. We also identified some of the overrepresented
transcription factors and associated miRNAs with high expression correlation values which could be useful in
cancer-related studies. The highly correlated groups were found to host experimentally validated composite regulatory
modules, in which Lmo2-GATA1 appeared as the predominant one. For many of RBP–miRNAs associations, coexpression
similarity was also evident among the associated miRNA common to given RBPs, supporting the Regulon
model, suggesting a common role and common control of these miRNAs by the associated RBPs. Based on our findings,
we propose that the observed characteristic distribution of regulatory sites in precursor miRNA sequence regions could be
critical inmiRNA transcription, processing, stability and formation and are important for therapeutic studies. Our findings
also support the recently proposed theory of self-sufficient mode of transcription by miRNAs, which states that miRNA
transcription can be carried out in host-independent mode too
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