Molecular analysis of the NAC gene family in rice

Genes that encode products containing a NAC domain, such as NO APICAL MERIS TEM (NAM) in petunia, CUP-SHAPED COTYLEDON2 (CUC2) and NAP in Arabidopsis t haliana, have crucial functions in plant development. We describe here mole cular aspects of the OsNAC genes that encode proteins with NAC domains in r ice (Oryza sativa L.). Sequence analysis revealed that the NAC genes in pla nts can be divided into several subfamilies, such as the NAM, ATAF, and OsN AC3 subfamilies. In rice, OsNAC1 and OsNAC2 are classified in the NAM subfa mily, which includes NAM and CUC2, while OsNAC5 and OsNAC6 fall into the AT AF subfamily. In addition to the members of these subfamilies, the rice gen ome contains the NAC genes OsNAC3, OsNAC4 (both in the OsNAC3 subfamily), O sNAC7, and OsNAC8. These results and Southern analysis indicate that the Os NAC genes constitute a large gene family in the rice genome. Each OsNAC gen e is expressed in a specific pattern in different organs, suggesting that t his family has diverse and important roles in rice development.