Molecular bases of rice grain size and quality for optimized productivity

Fine‐tuning of MPK6/3 phosphorylation by a lectin receptor‐like kinase LecRK‐VIII.2 regulates seed development

“…MAPK cascades are highly conserved signalling pathways in Arabidopsis and rice (Ren et al , 2023). We generated the transgenic lines 35S::AtLecRK‐VIII.2‐3 × Flag Nipponbare (NIP) (Table S1).…”

“…MPK6/3 are critical components for brassinolide (BR) signalling activation (Ren et al , 2023; Zhang and Zhang, 2022). The expression of OsWRKY53 , activated by pOsMPK6 to promote BR signalling and grain size, was elevated in the AtLecRK‐VIII.2 OE lines (Figure 1p).…”

“…Unexpectedly, the OsLecRK‐VIII.2 OE lines developed smaller grains than NIP plants (Figure 1t,x; Figure S4d), although they harboured higher pOsMPK6/3 level (Figure 1s). Given that both overexpression and suppression of rice G‐protein β subunit RGB1, a scaffold associating RLK and MAPK cascade components, produce short grains (Ren et al , 2023), it is possible that OsLecRK‐VIII.2 interacts with RGB1 or other G‐protein subunits to modulate grain size. Alternatively, excessively constitutive activation of OsMPK6/3 might break the balance between growth and defence, leading to the inhibited growth and developmental defects.…”

Dynamic monitoring of TGW6 by selective autophagy during grain development in rice

“…Population growth, climate change, and decreases in arable land area create demand for higher crop yields (Butardo et al ., 2019; Park et al ., 2019). Breeding new elite rice varieties with high‐yield and superior‐quality is definitely desired (Ren et al ., 2023). Grain size is a key determinant for both yield and quality and thus a prime target for cereal crop breeding.…”

“…Grain size is a key determinant for both yield and quality and thus a prime target for cereal crop breeding. However, rice yield and quality are usually antagonistic to each other due to the complex trade‐off between agronomic traits underlying grain size and grain quality, thereby preventing the application of the cloned grain‐associated genes deployed in rice breeding (Ren et al ., 2023). For example, increase in grain size by photosynthetic carbon fixation driving carbohydrates translocation from vegetative source organs generally results in the decrease in eating and cooking quality (ECQ) in grain, which stems from the accumulation of carbohydrates and its derivatives in the endosperm, such as storage starch (Butardo et al ., 2019).…”