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Using SP1 to control plastid development and yield in cereals

Periodic Reporting for period 1 - YIELDFACTOR (Using SP1 to control plastid development and yield in cereals)

Reporting period: 2016-03-07 to 2018-03-06

The addressed question:
A novel E3 ligase (SP1) in Arabidopsis controls plastid biogenesis, development and functions. This protein is essential for de-etiolation and early seedling establishment; it participates in leaf senescence; and it is involved in plant resistance to stress. All of these effects are highly correlated with plant growth and yield. Thus, the discovery of SP1 strongly suggests potential applications in agriculture, such as delaying leaf senescence to produce a “stay-green” phenotype, or controlling amyloplast development during grain filling by using SP1 to increase crop yield and quality, etc. This project investigated the functions of SP1 in rice and tomato to assess the application potential of SP1 in regulating the stress resistance ability of crop plants and improving yields. We made transgenic rice and tomato plants with manipulated SP1 expression, and assessed the growth, development and performance of the plants extensively, under both normal and stress conditions including drought and salt treatments.
The importance to society:
This project provided important knowledge of relevance in a number of areas, including plant genetics, plant breeding, plant biochemistry and plant development. As we know, plant plastids are responsible for producing important products such as starch, proteins and oils, which are highly correlated to yield. Therefore, the mechanisms of plastid development are critical to crop improvements. The discovery of SP1 strongly suggests potential applications in agriculture, such as delaying leaf senescence to produce a “stay-green” phenotype. Previous research had not investigated the functions and application potential of SP1 in crops, making this a cutting-edge project. This project also provided new insights into fundamental questions about the functions of SP1 in crops. The outputs of the project are relevant to food security, and will be of immediate interest to agricultural plant breeding strategies by suggesting novel strategies for increasing yields or grain quality, and/or by enabling crop plants to better deal with adverse environmental conditions (such as drought, high salinity, high temperature, etc.) which may occur more frequently in the future as a result of climate change. Improving crop stress tolerance may also enable crops to grow in places which are not currently suitable for crop growth.
The overall objective of this project was to investigate the function of SP1 in crops, including in relation to stress tolerance ability and yield-related parameters, by analysing transformants with altered SP1 expression levels.
The project has achieved most of its objectives and milestones for the funding period, with only relatively minor deviations.
During this project, we tried a few times to make transformants in B. distachyon, but did not get callus, and therefore (following consultation with programme administrators) we used tomato as research material instead of B. distachyon. For rice, we found that in this project the RNAi KD plants are not stable, and therefore we are making the CRISPR SP1 rice transgenic plants to achieve more stable loss of SP1 function; this is being pursued under the new BBSRC-funded project. Using the new CRISPR mutants, I will assess various parameters including some that proved to be difficult to analyse using the current RNAi KD lines: seed germination, seedling de-etiolation, leaf senescence, stress tolerance ability in the transformants.

All of these results might contribute highly to crop improvement.
trangenic plants of rice