Abstract: To reveal the molecular mechanism of metabolism in rice leaf sheath, this study investigated differential expression of proteins in rice leaf sheath of Jinhui 809 cultivar with large panicles and high setting percentage during grain filling by the method of differential proteomics. Twenty-three proteins with obviously different abundance were detected, and eleven of them were identified in function. Those functional proteins were classified into six categories according to their dynamic pattern of expression during grain filling. The first type showed down-regulation during grain filling, such as oxaloacetate decarboxylase alpha subunit. And the second one showed up-regulation at first and then down-regulation, such as ribulose bisphosphate carboxylase small chain and ADP-ribosylation factor 1. The third one was that down-regulated first, and then up and down regulated alternatively, such as auxin response factor, zinc finger, C3HC4 type family protein, vacuolar proton-ATPase, ribulose bisphosphate carboxylase/oxygenase activase. The forth type included rubisco binding-protein alpha subunit, showing an expression pattern of up and down regulation alternatively twice during grain filling. The fifth type performed a decreasing at first and then gradually increasing expression pattern , such as class II metallothionein-like protein 1A and geranylgeranyl diphosphate synthase. The sixth type was protein kinase family protein performing a gradually increasing expression pattern. These six different types of proteins involve in photosynthesis, hormone regulation, substance transportation, resistance response to plant senescence and cell signal diversion in leaf sheath respectively. They regulate the mechanism of sink to source transition together.

Key words: Rice (Oryza sativa L. ssp. indica), Leaf sheath, Proteome, Grain filling