title: Rubisco accumulation is important for the greening of the fln2-4 mutant in Arabidopsis.
abstract: The fructokinase-like protein2 (FLN2) is a component of the PEP complex. FLN2 knockout mutants displayed a delayed greening phenotype on sucrose-containing medium. Our previous work indicated that partial PEP activity is essential for its greening phenotype. In this study, we further report that sufficient Rubisco accumulation is critical for fln2-4 greening. Sugar serves many important functions, such as an energy source and signaling molecule. Through pharmacological experiments using a sugar analog and sugar signaling inhibitor, we demonstrate that sugar serves as energy to support the fln2-4 greening. Seed-reserve and photosynthetic CO2-fixation are the primary energy sources for early seedling growth. No obvious differences were observed in the seed-reserve of the wild-type and fln2-4 by comparing their seed size and dark-germination, indicating that the defective carbon fixation may account for the energy deficit in fln2-4 during its early seedling growth. The Rubisco content was low in fln2-4, but it rapidly accumulated during the greening of fln2-4. Expression of a nuclear-encoded rbcL gene facilitates Rubisco accumulation and partially complements the mutant defects. These results suggest that the Rubisco accumulation is critical for fln2-4 greening. In summary, the rapid Rubisco accumulation that depends on sufficient PEP activity is important for normal seedling growth.
authors.affiliation: Department of Biology, East China Normal University, Shanghai 200241, China. Electronic address: dielianhua1009@126.com.
authors.forename: Chao
authors.initials: C
authors.lastname: Huang
authors.affiliation: College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China. Electronic address: yuqing9860@shnu.edu.cn.
authors.forename: Qing-Bo
authors.initials: QB
authors.lastname: Yu
authors.affiliation: College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China. Electronic address: xbyuan@sibs.ac.cn.
authors.forename: Xin-Bo
authors.initials: XB
authors.lastname: Yuan
authors.affiliation: College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China. Electronic address: 852292191@qq.com.
authors.forename: Zi-Ran
authors.initials: ZR
authors.lastname: Li
authors.affiliation: College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China. Electronic address: 343458132@qq.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China. Electronic address: yelinshan0814@126.com.
authors.forename: Lin-Shan
authors.initials: LS
authors.lastname: Ye
authors.affiliation: Department of Biology, East China Normal University, Shanghai 200241, China. Electronic address: lxu@bio.ecnu.edu.cn.
authors.forename: Ling
authors.initials: L
authors.lastname: Xu
authors.affiliation: College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China. Electronic address: znyang@shnu.edu.cn.
authors.forename: Zhong-Nan
authors.initials: ZN
authors.lastname: Yang
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D018525:Germination; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics* / Q000378:metabolism; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism*; D012639:Seeds / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D013395:Sucrose; C000605310:FLN2 protein, Arabidopsis; D017853:Phosphotransferases (Alcohol Group Acceptor); D012273:Ribulose-Bisphosphate Carboxylase
keywords: Arabidopsis; Delayed greening; FLN2; PEP; Rubisco