Article by Florence Danila: Recipient of the ComBio 2015 ASPS Student Poster Prize
A large majority of the human population depends on rice (Oryza sativa) for survival. Rice production needs to increase by 50% to support a higher demand for food forecasted over the next 35 years due to an increasing human population. Traditional breeding can only increase rice yield by 1% per annum. Switching the less efficient C3 photosynthetic system of rice to use a more efficient C4 photosynthesis, would theoretically increase productivity by 50%. The aim of the C4 Rice Consortium is to add features of C4 photosynthesis to the C3 plant, rice. Therefore, it is essential to know whether rice can support the expected increase in metabolite flux between the leaf mesophyll (M) and bundle sheath (BS) cells after all the C4 biochemistry has been installed. The main pathway for metabolite flux is symplastic, i.e. via the plasmodesmata (PD) connecting M and BS cells. Comparison of the symplastic transport mechanisms between the C3 monocot crop, rice, and the C4 plant, Setaria viridis was done by looking at the PD density and pit field distribution between the M and BS cells. Electron microscopy and 3D immunolocalisation showed that Setaria (C4) has higher PD density and higher pit field area coverage on M/BS cell interface than rice (C3). Establishing the numerical difference in terms of PD connections between C3 and C4 plants is not only relevant for the C4 Rice Project but also in plant transport and modelling studies.
ARC Centre of Excellence for Translational Photosynthesis (Research School of Biology, Australian National University, Canberra, Australia). International Rice Research Institute (Laguna, Philippines). CSIRO Agriculture (Canberra, Australia).