Abstract：Bowman-Birk trypsin inhibitor (BBTI) is a type of cysteine-rich serine protease inhibitors, which is widely distributed in Leguminousaes, Gramineaes and Asteraceaes plants, and it plays an important role in protein storage and plant defense. There are 13 members of BBTI in rice genome, among which BBTI-9 and BBTI-10 are both pseudogenes, while others all include different amounts of Bowmen-Birk domains. To research the expression of BBTI proteins, 11 BBTI specific antibodies were generated mainly by the method of peptide sequence design and synthesis, and the expression patterns at leaf growth and seed germination stages of rice(Oryza sativa L. ssp. indica) were separately revealed by Western blot. The results indicated that BBTI showed specific temporal and spatial expression at various development stages in leaves. Expression level of BBTI-1, -2, -11, -12, and a-13 increased steadily with the growth of leaves, while that of BBTI-5, -6, and -8 reached the highest level at seedling stage. BBTI-3, -4, and -7 expressed most in 1cm at early seeding stage, presented expression in forms of modification and polymer during the leaf growth. Expression of The BBTI-8 protein was high in seeds and declined to the lowest level at 2 h after germination, and a degrading band of smaller molecular weight was expressed at 24 h. However, others were not found obvious changes in expression during seed germination. In attempt to compare the corresponding relationship of RNA and protein level, we collected statistics about MPSS tags of leaves at both seeding and tillering stages and seeds with germinating period. In sum, this experiment revealed differential expression patterns of BBTI proteins during growth and development stages in rice, providing important clues for a better understanding their functions.
