Biology subjects

Kareem, A.

Publications and source records attributed to Kareem, A..

7 recordsLinked to original sources

bioRxiv2025

Genome Sequencing, Molecular Marker Development and Genetic Diversity Assessment of Economically Important Vulnerable Tree Species Saraca asoca (Roxb.) W.J de Wilde

Saraca asoca, is an understory tree along streams in evergreen to semi-evergreen forests up to 600 m. It is an important tree in cultural tradition and medicinally significant. It is native to India and Sri Lanka. Globally the species is found to occur in India, Sri Lanka, Myanmar, Bangladesh. It was introduced in Malaysia. Within India, its found in Western Ghat and Eastern Ghat. It is occasionally planted in gardens. Saraca asoca is known for its extensive pharmacological properties, particularly its bark is used in treating menorrhagia, dysfunctional uterine bleeding, hemorrhagic dysentery, and other gynecological issues, it holds a prominent place in Ayurvedic medicine. This study was undertaken to sequence the whole genome of Saraca asoca using the Illumina HiSeq2500 platform, and evaluating the genetic diversity among samples from Kolluru and other locations in southern India through Genotyping by Sequencing (GBS). Analysis of 49 samples established genetic diversity relationships using a distance matrix. Sequencing yielded 1.6 Gb, covering 76% of the estimated genome size. The genome includes 764 million bases of repetitive DNA elements. A survey of Simple Sequence Repeats (SSRs) identified 584,615 SSRs, with 236,123 sequences containing SSRs. Utilizing the KEGG database, biosynthesis pathways for catechin and epicatechin within the flavonoid synthesis pathway were identified. This comprehensive genomic analysis of Saraca asoca (Sita Ashoka) provides critical insights for conservation efforts aimed at preserving this vulnerable species, Saraca asoca (Roxb.) Willd.

genomics↗

bioRxiv2024

Vascular Transcription Factor TMO5 Regulates PIN1 Polarity andOrganogenesis Downstream of MONOPTEROS in the Shoot Meristem

Plants continuously produce lateral organs, such as leaves and flowers, from the shoot apical meristem (SAM). This process is guided by the accumulation of the plant hormone auxin and the polar localization of the efflux protein PIN-FORMED1 (PIN1). The transcription factor MONOPTEROS (MP) plays a crucial role in orienting PIN1 polarity, thereby facilitating auxin-driven organogenesis. In this study, we investigated how MP regulates PIN1 polarity and organogenesis, discovering that the downstream vascular transcription factor TMO5 regulates PIN1 polarity non-cell-autonomously and promotes organ initiation in the SAM. Furthermore, we find that exogenous auxin and cytokinin can partially rescue the organ defects associated with loss of MP and TMO5 activity. Collectively, these findings uncover a novel role for TMO5 in controlling PIN1 polarity and driving organogenesis by coordinating hormonal signalling.

developmental biology↗

bioRxiv2024

Water availability determines plant regeneration fates

Wounding and hormones serve as diverse triggers for regeneration in animals and plants but how organisms determine regeneration outcomes remains largely unknown. Here, we demonstrated that wounded Arabidopsis tissues regenerate two distinct fates, wound-induced callus or de novo root formation, that are driven by antagonizing molecular pathways related to cambium and root development. We discovered that local water availability dictated these regeneration outcomes in Arabidopsis and tomato, with high water triggering root fate and low water initiating callus fate. Moreover, distinct spatial distributions of auxin response maxima were critical for fate progression and water availability regulated these auxin maxima through the hormones ethylene and jasmonic acid. We propose that water availability determines environmental control of regeneration plasticity with applied potential for improving regeneration in agriculture.

plant biology↗

bioRxiv2023

Auxin signaling in the cambium promotes tissue attachment and vascular development during Arabidopsis thaliana graft formation

The remarkable ability of plants to regenerate wounds is exemplified during the process of plant grafting when two plants are cut and joined together to grow as one. During graft healing, damaged tissues attach, cells proliferate and the vasculatures connect to form a graft union. The plant hormone auxin plays a central role and mutants perturbed in auxin response fail to successfully graft. Here, we investigated the role of individual cell types and their response to auxin during Arabidopsis thaliana graft formation. By employing an inducible misexpression system, we blocked auxin response in individual cell types using the bodenlos mutation. We found that auxin signaling in procambial tissues was critical for both successful tissue attachment and also for vascular differentiation. In addition, we found that auxin signaling was required for cell divisions of the procambial cells during graft formation. Loss of function mutants in cambial pathways also perturbed attachment and phloem reconnection. We propose that cambium and procambium are key tissues that allow both tissue attachment and vascular differentiation during successful grafting. Our study thus refines our knowledge of graft development and furthers our understanding of regeneration biology and the function of cambium.

plant biology↗

bioRxiv2020

Regulation of touch dependant de novo root regeneration in Arabidopsis

The versatile regeneration capability of leaves enable even a detached Arabidopsis leaf to yield two kinds of regenerative responses namely, wound healing at the cut end in form of callus formation or de novo root regeneration (DNRR). Using various experimental approaches, we show that the factor favouring DNRR over callus formation seems to be a mechanical cue, possibly touch, at the cut end of the detached leaf. Here, we show that the forced expression of a PLETHORA transcription factor can bypass the need for touch to initiate DNRR. Our findings provide a genetic frame-work for touch dependant DNRR and suggest that a core PLT transcription regulatory module acts in response to mechano-sensing stimuli.

plant biology↗

bioRxiv2020

Age, wound size and position of injury - dependent vascular regeneration assay in growing leaves

BackgroundRecurring damage to aerial organs of plants necessitates their prompt repair, particularly their vasculature. While vascular regeneration assay in aerial plant parts such as stem and inflorescence stalk are well established, those on leaf vasculature remained unexplored. Recently we established a new vascular regeneration assay in growing leaf and discovered the underlying molecular mechanism. ResultsHere we describe the detailed stepwise method of incision and the regeneration assay used for studying the leaf vascular regeneration. By using a combination of micro-surgical perturbations, brightfield microscopy and other experimental approaches, our new findings show that the regeneration efficiency decreases with aging of the leaf, and increases with the nearness of the wound towards the proximal end of the leaf. ConclusionThis easy-to-master vascular regeneration assay is an efficient and rapid method to study the mechanism of vascular regeneration in growing leaves. It can be readily adapted for other plant species and can be combined with cellular and molecular biology techniques.

plant biology↗

bioRxiv2018

Impact of Chronic Total Occlusion Lesion Length onSix-month Angiographic and 2-year Clinical Outcomes

BackgroundSuccessful chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is known to be associated with improved clinical outcomes compared with failed CTO PCI. However, it is not clear whether the angiographic and clinical outcomes of long CTO lesionis different with those of short CTO lesion in the drug eluting stent (DES) era.\n\nMethod sand ResultsA total of 235 consecutive patients underwent successful CTO intervention were divided into two groups according the CTO lesion length. Six-month angiographic and two-year clinical outcomes were compared between the two groups. The baseline clinical characteristics were similar between the two groups except prior PCI was more frequent in long CTO group whereas bifurcation lesion was more frequent in the short CTO group. In-hospital complications were similar between the two groups except intimal dissection was more frequent in long CTO group. Both groups had similar angiographic outcomes at 6 months and clinical outcomes up to 2 years except the incidence of repeat PCI, predominantly target vessel revascularization (TVR) was higher in long CTO group. In multivariate analysis, long CTO was an important predictor for repeat PCI (OR;4.26, CI 1.53-11.9, p=0.006).\n\nConclusionThe safety profile, angiographic and 2-year clinical outcomes were similar between the two groups except higher incidence of repeat PCI in long CTO group despite of successful PCI with DESs.

physiology↗