Biology subjects

Bartley, L.

Publications and source records attributed to Bartley, L..

3 recordsLinked to original sources

bioRxiv2023

Altered cell wall hydroxycinnamate composition impacts leaf and canopy-level CO2-uptake and water-use in rice

Cell wall properties can play a major role in determining photosynthetic carbon-uptake and water-use through impacts on mesophyll conductance (CO2 diffusion from substomatal cavities into photosynthetic mesophyll cells) and leaf hydraulic conductance (water movement from xylem, through leaf tissue to stomata). Consequently, modification of cell wall properties is proposed as a major path for improving photosynthesis and crop water-use efficiency. We tested this using two independent transgenic rice lines that overexpress the rice OsAT10 gene (a "BAHD" CoA acyltransferase) which altered cell wall hydroxycinnamic acid content (greater para-coumaric acid and lower ferulic acid). Plants were grown under high and low water-levels and traits related to leaf anatomy, cell wall composition, gas exchange and hydraulics, plant biomass, and canopy-level water-use were measured. Alteration of hydroxycinnamic acid content led to significant decreases in mesophyll cell wall thickness (-14%), and increased mesophyll conductance (+120%) and photosynthesis (+22%). However, concomitant increases in stomatal conductance negated increased photosynthesis, resulting in no change in intrinsic water-use efficiency (ratio of photosynthesis/stomatal conductance). The leaf hydraulic conductance was also unchanged; however, the transgenics showed small, but significant increase in above-ground biomass (+12.5%), and canopy-level water-use efficiency (+8.8%; ratio of above-ground biomass/ water-used) and performed better under low water-level. Our results demonstrate that changes in cell wall composition, specifically hydroxycinnamic acid content, can increase mesophyll conductance and photosynthesis in C3 cereal crops like rice. However, attempts to improve photosynthetic water-use efficiency will need to enhance mesophyll conductance and photosynthesis whilst maintaining or decreasing stomatal conductance.

plant biology↗

bioRxiv2022

Isolation and Transfection of Rice Egg Cells and Zygotes for Cellular Localization

Due to the difficulty in accessing to gametes and zygotes in flowering plants, which are controlled in single cells deeply embedded in multiple tissues, little is known about how the initiation of plant embryogenesis may reflect or contrast from such systems in other eukaryotes. In this study we has developed an approach of isolation and transfection of rice egg cells and zygotes for cellular localization of rice cell cycle factors (KRP5, KRP4 and FB3), which opened a pathway to monitor protein expression in rice egg cells and zygotes at different developmental stages. The advantageous feature of isolated rice cells may serve as an ideal system for studying the molecular mechanism underlying the rice zygotic division to initiate seed formation.

cell biology↗

bioRxiv2022

A CDKB/KRP/FB3 cell cycle core complex functions in rice gametes and zygotes

The cell cycle controls division and proliferation of all eukaryotic cells and is tightly regulated at multiple checkpoints by complexes of core cell cycle proteins. Due to the difficulty in accessing female gametes and zygotes of flowering plants, little is known about the molecular mechanisms underlying initiation embryogenesis despite the crucial importance of this process for seed crops. In this study, we reveal four levels of factors involved in rice zygotic cell cycle control and characterize their functions and regulation. Protein-protein interaction studies, including within zygote cells, and in vitro biochemical analyses delineate a model of the zygotic cell cycle core complex for rice. In this model, CDKB1, a major regulator of plant mitosis, is a cyclin (CYCD5)-dependent kinase; its activity is coordinately inhibited by two cell cycle inhibitors, KRP4 and KRP5; and both KRPs are regulated via F-box protein 3 (FB3)-mediated proteolysis. Supporting their critical role in controlling the rice zygotic cell cycle, mutations in KRP4, KRP5, and FB3 result in the compromised function of sperm cells and abnormal organization of female germ units, embryo and endosperm, thus significantly reducing seed-set rates. This work helps reveals regulatory mechanisms controlling the zygotic cell cycle toward seed formation in angiosperms.

cell biology↗