J Integr Plant Biol. ›› 2018, Vol. 60 ›› Issue (2): 94-111.DOI: 10.1111/jipb.12631

Special Issue: Rice Genomics and Agriculture CRISPR

• Research Articles • Previous Articles     Next Articles

FRUCTOKINASE-LIKE PROTEIN 1 interacts with TRXz to regulate chloroplast development in rice

Lei He1†, Sen Zhang1†, Zhennan Qiu1, Juan Zhao1, Wendan Nie2, Haiyan Lin1, Zhengge Zhu2, Dali Zeng1, Qian Qian1* and Li Zhu1*   

  1. 1State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
    2Hebei Key Laboratory of Molecular and Cellular Biology, Hebei Normal University, Shijiazhuang 050024, China
  • Received:2017-12-18 Accepted:2018-01-05 Published:2018-02-13
  • About author:These authors contributed equally to this work.
    **Correspondence: Email: Qian Qian (qianqian188@hotmail.com; Li Zhu (zhuli05@caas.cn; Dr. Zhu is fully responsible for the distribution of all materials associated with this article)


Chloroplast genes are transcribed by the plastid-encoded RNA polymerase (PEP) or nucleus-encoded RNA polymerase. FRUCTOKINASE-LIKE PROTEINS (FLNs) are phosphofructokinase-B (PfkB)-type carbohydrate kinases that act as part of the PEP complex; however, the molecular mechanisms underlying FLN activity in rice remain elusive. Previously, we identified and characterized a heat-stress sensitive albino (hsa1) mutant in rice. Map-based cloning revealed that HSA1 encodes a putative OsFLN2. Here, we further demonstrated that knockdown or knockout of the OsFLN1, a close homolog of HSA1/OsFLN2, considerably inhibits chloroplast biogenesis and the fln1 knockout mutants, created by clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associate protein 9, exhibit severe albino phenotype and seedling lethality. Moreover, OsFLN1 localizes to the chloroplast. Yeast two-hybrid, pull-down and bimolecular fluorescence complementation experiments revealed that OsFLN1 and HSA1/OsFLN2 interact with THIOREDOXINZ (OsTRXz) to regulate chloroplast development. In agreement with this, knockout of OsTRXz resulted in a similar albino and seedling lethality phenotype to that of the fln1 mutants. Quantitative reverse transcription polymerase chain reaction and immunoblot analysis revealed that the transcription and translation of PEP-dependent genes were strongly inhibited in fln1 and trxz mutants, indicating that loss of OsFLN1, HSA1/OsFLN2, or OsTRXz function perturbs the stability of the transcriptionally active chromosome complex and PEP activity. These results show that OsFLN1 and HSA1/OsFLN2 contribute to chloroplast biogenesis and plant growth.

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