The chloroplast is important organelle responsible for photosynthesis and various bio-
synthetic functions essential to green plants. However, the regulatory mechanism of chloroplast development remains elusive. Here, we characterized a mutant with defective chloroplasts in rice (Oryza sativa L.) named it albino and lethal 13(osal13), which exhibited a distinct albino phenotype in leaves, eventually leading to seedling lethality. Molecular cloning revealed that OsAL13 encodes a novel protein in rice for which no homologous gene or known conserved domain was found. Analysis of the biological characteristics showed that the RNAi2 leaf was completely albino phenotype, the root and shoot lengths were significantly inhibited compared with wild type. Transmission electron microscopy indicated that RNAi2 were defective in chloroplast development. Overexpression of OsAL13 resulted the photosynthetic rate increase, So the total grain number per panicle also would be significantly increase. Besides, OsAL13 was located in chloroplast and constitutively expressed in various tissues, including green and non-green tissues. In addition, disruption of OsAL13 resulted in altered expression of plastid-encoded polymerases and nuclear-encoded chloroplast genes, OsAL13 also affected hormone levels in plant tissues. Therefore, our results provide new insights into the role of OsAL13 in regulating chloroplast development
in rice.