Biology subjects

Davda, J. N.

Publications and source records attributed to Davda, J. N..

3 recordsLinked to original sources

bioRxiv2025

CDM1 is required for meiotic progression and genome integrity during male meiosis in Arabidopsis

Microsporogenesis involves the integration of meiosis with the developmental program leading to formation of microspores from meiocytes. The CALLOSE DEFICIENT MICROSPORE 1 (CDM1) gene of Arabidopsis has been previously characterized as being required for callose metabolism and its loss results in defects in microspore wall development, degeneration of meiotic products, and male sterility. We report here that CDM1 is required for normal meiosis I progression, meiotic chromosome organization, and maintenance of DNA integrity. CDM1 is part of the ATM dependent DNA damage response in dividing vegetative tissues. The cdm1 mutant shows defects in meiotic chromosome condensation, arrest at metaphase I, susceptibility to chromosome breakage in rDNA regions, defects in positioning of the products of meiosis, and increased expression of recombination related genes. However, fidelity of chromosome segregation is not affected. Furthermore, the meiotic phenotype of cdm1 is independent of SPO11 induced meiotic double strand breaks. CDM1 protein displays granular localization in meiosis throughout the cytoplasm that resembles that of mRNP granules. The results show that CDM1 is required for maintenance of proper chromosome organization and DNA integrity in the course of male meiosis. The chromosomal defects in cdm1 may originate from regions of defective or incomplete replication. HighlightCDM1 expression is DNA damage inducible in Arabidopsis mitotic cells. CDM1 is required for genome integrity in male meiosis independent of SPO11-induced DNA breaks, suggesting a role in regulation of premeiotic replication repair.

plant biology↗

bioRxiv2024

Sporophyte Directed Gametogenesis via the Ubiquitin Proteasome System

Plants alternate between diploid sporophyte and haploid gametophyte generations. In mosses which retain features of ancestral land plants, the gametophyte is dominant and has an independent existence. However, in flowering plants the gametophyte has undergone evolutionary reduction to just a few cells enclosed within the sporophyte. The gametophyte is thought to retain genetic control of its development even after reduction. Here we demonstrate that male gametophyte development in Arabidopsis, long considered to be autonomous, is also under genetic control of the sporophyte via a repressive mechanism involving large-scale regulation of protein turnover. We identify an Arabidopsis gene SHUKR as an inhibitor of male gametogenesis. SHUKR is unrelated to proteins of known function and acts sporophytically in meiosis to control gametophyte development by negatively regulating expression of a large set of ubiquitination genes specific to post-meiotic gametogenesis. This control is late-emerging as SHUKR homologs are found only in eudicots. We show that SHUKR is rapidly evolving under positive selection suggesting that variation in control of protein turnover during male gametogenesis has played an important role in evolution within eudicots.

plant biology↗

bioRxiv2020

An Inexpensive RT-PCR Endpoint Diagnostic Assay for SARS-CoV-2 Using Nested PCR: Direct Assessment of Detection Efficiency of RT-qPCR Tests and Suitability for Surveillance

With a view to extending testing capabilities for the ongoing SARS-CoV-2 pandemic we have developed a test that lowers cost and does not require real time quantitative reverse transcription polymerase chain reaction (RT-qPCR). We developed a reverse transcription nested PCR endpoint assay (RT-nPCR) and showed that RT-nPCR has comparable performance to the standard RT-qPCR test. In the course of comparing the results of both tests, we found that the standard RT-qPCR test can have low detection efficiency (less than 50%) in a real testing scenario which may be only partly explained by low viral representation in many samples. This finding points to the importance of directly monitoring detection efficiency in test environments. We also suggest measures that would improve detection efficiency.

molecular biology↗