Biology subjects

Koteyeva, N.

Publications and source records attributed to Koteyeva, N..

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↗

bioRxiv2021

Mesophyll conductance response to short-term changes in pCO2 is related to leaf anatomy and biochemistry in diverse C4 grasses

O_LIMesophyll CO2 conductance (gm) in C3 species responds to short-term (minutes) changes in environment potentially due to changes in some leaf anatomical and biochemical properties and due to measurement artifacts. Compared to C3 species, there is less information about gm responses to short-term changes in environment conditions like pCO2 across diverse C4 species and the potential determinants of these responses. C_LIO_LIUsing 16 diverse C4 grasses we investigated the response of gm to short-term changes in CO2 and how this response related to the leaf anatomical and biochemical traits. C_LIO_LIFor all the measured C4-grasses gm increased as CO2 decreased; however, the percent change in gm varied (+13% to +250%) and significantly related to percent changes in leaf transpiration efficiency (TEi). The percent increase in gm was highest in grasses with thinner mesophyll cell walls and greater leaf nitrogen, activities of phosphoenolpyruvate carboxylase (PEPC), Rubisco and carbonic anhydrase, and a higher affinity of PEPC for bicarbonate. C_LIO_LIOur study demonstrates that CO2 response of gm varies greatly across diverse C4 grasses and identifies the key leaf anatomical and biochemical traits related to this variation. These findings have implications for improving C4 photosynthetic models, and in attempts to improve TEi through manipulation of gm. C_LI

plant biology↗

bioRxiv2020

Leaf cell wall properties and stomatal density influence oxygen isotope enrichment of leaf water

Oxygen isotopic composition ({Delta}18OLW) of leaf water can help improve our understanding of how anatomy interacts with physiology to influence leaf water transport. Leaf water isotope models of {Delta}18OLW such as the Peclet effect model have been developed to predict {Delta}18OLW, and it incorporates transpiration rate (E) and the mixing length between unenriched xylem water and enriched mesophyll water, which can occur in the mesophyll (Lm) or veins (Lv). Here we used two cell wall composition mutants grown under two light intensities and RH to evaluate the effect of cell wall composition on {Delta}18OLW. In maize (Zea mays), the compromised ultrastructure of the suberin lamellae in the bundle sheath of the ALIPHATIC SUBERIN FERULOYL TRANSFERASE mutant (Zmasft) reduced barriers to apoplastic water movement, resulting in higher E and Lv and, consequently, lower {Delta}18OLW. In cellulose synthase-like F6 (Cslf6) mutants and wildtype of rice (Oryza sativa), the difference in {Delta}18OLW in plants grown under high and low growth light intensity co-varied with their differences in stomatal density. These results show that cell wall composition and stomatal density influence {Delta}18OLW by altering the Peclet effect and that stable isotopes can facilitate the development of a physiologically and anatomically explicit water transport model.

plant biology↗