Browsing by Author "Kumar, Pankaj"

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CRISPR/Cas9 directed editing of lycopene epsilon-cyclase modulates metabolic flux for β-carotene biosynthesis in banana fruit
(Elsevier B.V., 2020) Kaur, Navneet; Alok, Anshu; Shivani; Kumar, Pankaj; Kaur, Navjot; Awasthi, Praveen; Chaturvedi, Siddhant; Pandey, Pankaj; Pandey, Ashutosh; Pandey, Ajay K.; Tiwari, Siddharth
Banana is one of the most economically important fruit crops worldwide. Genetic improvement in banana is a challenging task due to its parthenocarpic nature and triploid genome. Genetic modification of crops via the CRISPR/Cas9 module has emerged as a promising tool to develop important traits. In the present work, a CRISPR/Cas9-based approach was used to develop the β-carotene-enriched Cavendish banana cultivar (cv.) Grand Naine (AAA genome). The fifth exon of the lycopene epsilon-cyclase (LCYε) gene was targeted. The targeting specificity of the designed guide-RNA was also tested by its ability to create indels in the LCYε gene at the A genome of cv. Rasthali (AAB genome). Sequence analysis revealed multiple types of indels in the genomic region of Grand Naine LCYε (GN-LCYε). Metabolic profiling of the fruit pulp of selected edited lines showed enhanced accumulation of β-carotene content up to 6-fold (~24 μg/g) compared with the unedited plants. These lines also showed either an absence or a drastic reduction in the levels of lutein and α-carotene, suggesting metabolic reprogramming, without any significant effect on the agro-morphological parameters. In addition, differential expression of carotenoid pathway genes was observed in the edited lines in comparison to unedited plants. Overall, this is the first report in banana to improve nutritional trait by using a precise genome editing approach.
Ethylene-mediated regulation of a ripening-specific N-glycan-processing enzyme β-D-N-Acetylhexosaminidase
(Springer Nature Publishing AG, 2025) Irfan, Mohammad; Kumar, Pankaj; Datta, Asis
N-glycoproteins in plants play a critical role in various biological processes such as plant stress response, seed development, and fruit ripening. Further, N-glycans and N-glycan-processing enzymes have been identified as critical regulators of fruit ripening in various fruit crop including tomato. Fruit ripening, a multifaceted process influenced by diverse factors is controlled by the upregulation of cell wall degradation enzymes. Among these, N-glycan-processing enzymes, specifically β-D-N-acetylhexosaminidase (β-Hex), are involved in ripening-associated fruit softening, and its suppression enhances fruit shelf life and firmness in both climacteric and non-climacteric fruits. Ethylene is among the various factors that regulates the ripening-specific expression of β-Hex. Notably, ethylene response factor 6 (SlERF6), also known as SlERF.E4, has been identified as a potential transcriptional regulator of β-Hex expression. However, in order to get deeper insights, a thorough understanding of the specific ethylene-mediated control of β-Hex during ripening is crucial. Thus, we present a protocol for investigating the ethylene-mediated regulation of this crucial ripening-related enzyme β-D-N-acetylhexosaminidase.
Fruit ripening specific expression of β-D-N-acetylhexosaminidase (β-Hex) gene in tomato is transcriptionally regulated by Ethylene Response Factor SlERF.E4
(Elsevier B.V., 2022) Irfan, Mohammad; Kumar, Pankaj; Kumar, Vinay; Datta, Asis
N-glycans and N-glycan processing enzymes are key players in regulating the ripening of tomato (Solanum lycopersicum) fruits, a model for fleshy fruit ripening. β-D-N-acetylhexosaminidase (β-Hex) is a N-glycan processing enzyme involved in fruit ripening. The suppression of β-Hex results in enhanced fruit shelf life and firmness in both climacteric and non-climacteric fruits. Previously, we have shown that ripening specific expression of β-Hex is regulated by RIPENING INHIBITOR (RIN), ABSCISIC ACID STRESS RIPENING 1 (SlASR1) and ethylene. However, the precise mechanism of ethylene-mediated regulation of β-Hex remains elusive. To gain insights into this, we have performed 5’ deletion mapping of tomato β-Hex promoter and a shorter promoter fragment (pD-200, 200 bp upstream to translational start site) is identified, which was found critical for spatio-temporal transcriptional regulation of β-Hex. Further, site specific mutagenesis in RIN and ASR1 binding sites in pD-200 provides key insights into ripening specific promoter activity. Furthermore, induction of GUS activity by ethylene, yeast one hybrid assay and EMSA identify Ethylene Response Factor SlERF.E4 as a positive regulator of β-Hex. Taken together, our study suggest that SlERF.E4 together with RIN and SlASR1 transcriptionally regulates β-Hex and all these three proteins are essential for fruit ripening specific expression of β-Hex in tomato.
N-glycan remodeling by α-D-mannosidase and β-D-N-acetylhexosaminidase regulates fruit softening, redox balance, and post-harvest pathogen resistance
(John Wiley & Sons, 2025) Irfan, Mohammad; Kumar, Pankaj; Kumar, Vinay; Ahmad, Irshad; Ansari, Sekhu; Ghosh, Sumit; Datta, Asis
Post-harvest loss of fruits and vegetables poses significant challenges to food security and economic sustainability, primarily due to ripening-associated excessive softening that shortens shelf life and increases susceptibility to pathogens. N-glycans, N-glycoproteins, and their processing enzymes are integral to various plant processes, including fruit ripening. Among these, α-D-mannosidase (α-Man) and β-D-N-acetylhexosaminidase (β-Hex) are key ripening-specific enzymes that modulate fruit softening. Previously, we have shown that RNAi-mediated suppression of α-Man or β-Hex improves fruit shelf life and firmness in both climacteric and non-climacteric fruits. However, the underlying molecular and biochemical basis of fruit softening regulation by α-Man and β-Hex was not well understood. In this study, we developed transgenic tomato (Solanum lycopersicum) plants by silencing α-Man and β-Hex simultaneously using RNAi. Suppression of these enzymes reduces N-glycoprotein degradation, downregulates pectin dissolution, and inhibits ripening-related gene expression. RNAi fruits exhibited enhanced shelf life, greater firmness, reduced reactive oxygen species (ROS) accumulation and increased resistance against post-harvest pathogens without affecting plant growth, fruit development, yield, or nutritional quality. To further explore the molecular mechanism of α-Man and β-Hex function, we purified and quantified N-glycans in RNAi fruits and other ripening-impaired mutants, identifying key N-glycan species. We also carried out iTRAQ-based quantitative proteome profiling to investigate the abundance of proteins in ripened fruit affected by silencing of α-Man and β-Hex. Molecular insights revealed that N-glycan processing and degradation are key events during ripening, influencing cell wall softening, fruit redox state, and post-harvest quality attributes. This study highlights the potential of co-silencing α-Man and β-Hex as a novel approach to extending the shelf life of fruits, regardless of their climacteric behavior, without compromising quality or yield.
Recent insights into plant circadian clock response against abiotic stress
(Springer Nature Publishing AG, 2022) Sharma, Megha; Irfan, Mohammad; Kumar, Arun; Kumar, Pankaj; Datta, Asis
The circadian clock is a cell autonomously and endogenously regulated biological timekeeper that detects changes in environmental stimuli and generates 24-h rhythms that are synched with day to day and periodic oscillations to govern many biological functions. Plant's circadian clocks enable them to anticipate environmental changes by modifying their physiological and biological traits to improve plant fitness. The internal circadian clock not only aids fitness but also allows the plant to time-gate the response to environmental stimuli. The latest evidence on the circadian clock suggests that the clock regulates/modulates the expression of abiotic stress-responsive pathways to improve tolerance to stresses without hampering plant growth. In turn, stress signaling also influences the activity of several clock components. This review emphasizes the interplay of the biological circadian clock with abiotic stress-responsive pathways (drought, heat, cold, and salt) for plant growth and survival as well as for stress resilience. A better comprehension of these mechanisms could aid in the development of genetic tools to improve breeding procedures and plant stress tolerance, thereby increasing crop yield and quality under changing ecological conditions.
Unraveling the role of tomato Bcl-2-associated athanogene (BAG) proteins during abiotic stress response and fruit ripening
(Springer Nature Publishing AG, 2021) Irfan, Mohammad; Kumar, Pankaj; Ahmad, Irshad; Datta, Asis
B-cell lymphoma2 (Bcl-2)-associated athanogene (BAG) family proteins are evolutionary conserved across all eukaryotes. These proteins interact with HSP70/HSC70 and function as co-chaperones during stress response and developmental pathways. Compared to the animal counterpart, the BAG proteins in plants are much less studied and primarily Arabidopsis BAG proteins have been identified and characterized for their role in programmed cell death, homeostasis, growth and development, abiotic and biotic stress response. Here, we have identified BAG protein family (SlBAGs) in tomato, an economically important and a model fruit crop using genome-wide scanning. We have performed phylogenetic analysis, genes architecture assessment, chromosomal location and in silico promoter analysis. Our data suggest that SlBAGs show differential tissue specific expression pattern during plant development particularly fruit development and ripening. Furthermore, we reported that expression of SlBAGs is modulated during abiotic stresses and is regulated by stress hormones ABA and ethylene. In planta subcellular localization reveals their diverse subcellular localization, and many members are localized in nucleus and cytoplasm. Like previous reports, our protein–protein interaction network and yeast two-hybrid analysis uncover that SlBAGs interact with HSP70. The current study provides insights into role of SlBAGs in plant development particualry fruit ripening and abiotic stress response.