title: NOA1 functions in a temperature-dependent manner to regulate chlorophyll biosynthesis and Rubisco formation in rice.
abstract: NITRIC OXIDE-ASSOCIATED1 (NOA1) encodes a circularly permuted GTPase (cGTPase) known to be essential for ribosome assembly in plants. While the reduced chlorophyll and Rubisco phenotypes were formerly noticed in both NOA1-suppressed rice and Arabidopsis, a detailed insight is still necessary. In this study, by using RNAi transgenic rice, we further demonstrate that NOA1 functions in a temperature-dependent manner to regulate chlorophyll and Rubisco levels. When plants were grown at 30°C, the chlorophyll and Rubisco levels in OsNOA1-silenced plants were only slightly lower than those in WT. However, at 22°C, the silenced plants accumulated far less chlorophyll and Rubisco than WT. It was further revealed that the regulation of chlorophyll and Rubisco occurs at the anabolic level. Etiolated WT seedlings restored chlorophyll and Rubisco accumulations readily once returned to light, at either 30°C or 15°C. Etiolated OsNOA1-silenced plants accumulated chlorophyll and Rubisco to normal levels only at 30°C, and lost this ability at low temperature. On the other hand, de-etiolated OsNOA1-silenced seedlings maintained similar levels of chlorophyll and Rubisco as WT, even after being shifted to 15°C for various times. Further expression analyses identified several candidate genes, including OsPorA (NADPH: protochlorophyllide oxidoreductase A), OsrbcL (Rubisco large subunit), OsRALyase (Ribosomal RNA apurinic site specific lyase) and OsPuf4 (RNA-binding protein of the Puf family), which may be involved in OsNOA1-regulated chlorophyll biosynthesis and Rubisco formation. Overall, our results suggest OsNOA1 functions in a temperature-dependent manner to regulate chlorophyll biosynthesis, Rubisco formation and plastid development in rice.
authors.affiliation: Key Laboratory of Plant Functional Genomics and Biotechnology, Education Department of Guangdong Province, South China Agricultural University, Guangzhou, China.
authors.forename: Qiaosong
authors.initials: Q
authors.lastname: Yang
authors.forename: Han
authors.initials: H
authors.lastname: He
authors.forename: Heying
authors.initials: H
authors.lastname: Li
authors.forename: Hua
authors.initials: H
authors.lastname: Tian
authors.forename: Jianjun
authors.initials: J
authors.lastname: Zhang
authors.forename: Liguang
authors.initials: L
authors.lastname: Zhai
authors.forename: Jiandong
authors.initials: J
authors.lastname: Chen
authors.forename: Hong
authors.initials: H
authors.lastname: Wu
authors.forename: Ganjun
authors.initials: G
authors.lastname: Yi
authors.forename: Zheng-Hui
authors.initials: ZH
authors.lastname: He
authors.forename: Xinxiang
authors.initials: X
authors.lastname: Peng
mesh_terms: D001483:Base Sequence; D002734:Chlorophyll / Q000096:biosynthesis*; D017931:DNA Primers; D020868:Gene Silencing; D020411:Oligonucleotide Array Sequence Analysis; D012275:Oryza / Q000201:enzymology / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012273:Ribulose-Bisphosphate Carboxylase / Q000096:biosynthesis*; D013696:Temperature; D014158:Transcription, Genetic
chemical_list: D017931:DNA Primers; D010940:Plant Proteins; D002734:Chlorophyll; D012273:Ribulose-Bisphosphate Carboxylase