Cold stress has always been a significant limitation for plant development and causes substantial decreases in crop yield. Some temperate plants, such as Arabidopsis, have the ability to carry out internal adjustment, which maintains and checks the metabolic machinery during cold temperatures. This cold acclimation process requires prior exposure to low, chilling temperatures to prevent damage during subsequent freezing stress and maintain the overall wellbeing of the plant despite the low-temperature conditions. In comparison, plants of tropical and subtropical origins, such as rice, are sensitive to chilling stress and respond differently to low-temperature stress. Plants have evolved various physiological, biochemical, and molecular mechanisms to sense and respond to low-temperature stress, including membrane modifications and cytoskeletal rearrangement. Moreover, the transient increase in cytosolic calcium level leads to the activation of many calcium-binding proteins and calcium-dependent protein kinases during low-temperature stress. Recently, mitogen-activated protein kinases have been found to regulate low-temperature signaling through ICE1. Besides, epigenetic control plays a crucial role during the cold stress response. This review primarily focuses on low-temperature stress experienced by plants and their strategies to overcome it. We have also reviewed recent progress and previous knowledge for a better understanding of plant cold stress response.
Medicinal plants have been used from the beginning of human civilization, which is mostly evident from the ancient script and traditional herbal medicine recipe. Despite the historically enriched demonstration about the use of plant as therapeutics, the pharmaceutical industries lack interest on phytochemical research compared with synthetic drug. Mostly, the absence of information about plant‐based medicinal therapeutics is responsible to draw the attention of researchers to think about natural products as potential drug for detrimental diseases, such as cancer. This review will cover about clinically successful plant‐based anticancer drugs and underappreciated, but potential, drugs to bridge the information gap between plant biologists and clinical researchers. Additionally, unprecedented advancement of synthetic chemistry, omics study to pin point the target genes/proteins, and efficient drug delivery system have made it easier for researchers to develop a phytochemical as an efficient anticancer drug.
Asymmetric cell division generates different cell types and is a feature of development in multicellular organisms. Prior to asymmetric cell division, cell polarity is established. Maize (Zea mays) stomatal development serves as an excellent plant model system for asymmetric cell division, especially the asymmetric division of the subsidiary mother cell (SMC). In SMCs, the nucleus migrates to a polar location after the accumulation of polarly localized proteins but before the appearance of the preprophase band. We examined a mutant of an outer nuclear membrane protein that is part of the LINC (linker of nucleoskeleton and cytoskeleton) complex that localizes to the nuclear envelope in interphase cells. Previously, maize linc kash sine-like2 (mlks2) was observed to have abnormal stomata. We confirmed and identified the precise defects that lead to abnormal asymmetric divisions. Proteins that are polarly localized in SMCs prior to division polarized normally in mlks2. However, polar localization of the nucleus was sometimes impaired, even in cells that have otherwise normal polarity. This led to a misplaced preprophase band and atypical division planes. MLKS2 localized to mitotic structures; however, the structure of the preprophase band, spindle and phragmoplast appeared normal in mlks2. Timelapse imaging revealed that mlks2 has defects in pre-mitotic nuclear migration towards the polarized site and unstable position at the division site after formation of the preprophase band. Overall, our results show that nuclear envelope proteins promote pre-mitotic nuclear migration and stable nuclear position and that the position of the nucleus influences division plane establishment in asymmetrically dividing cells.
SWEET transporters are a unique class of sugar transporters that play vital roles in various developmental and physiological processes in plants. While the functions of SWEETs have been well established in model plants such as Arabidopsis, their functions in economically important fruit crops like pineapple have not been well studied. Here we aimed to investigate the substrate specificity of pineapple SWEETs by comparing the protein sequences of known glucose and sucrose transporters in Arabidopsis with those in pineapple. Our genome-wide approach and 3D structure comparison showed that the Arabidopsis SWEET8 homolog in pineapple, AcSWEET10, shares similar sequences and protein properties responsible for glucose transport. To determine the functional conservation of AcSWEET10, we tested its ability to complement glucose transport mutants in yeast and analyzed its expression in stamens and impact on the microspore phenotype and seed set in transgenic Arabidopsis. The results showed that AcSWEET10 is functionally equivalent to AtSWEET8 and plays a critical role in regulating microspore formation through the regulation of the Callose synthase5 (CalS5), which highlights the importance of SWEET transporters in pineapple. This information could have important implications for improving fruit crop yield and quality by manipulating SWEET transporter activity.