Download Isolation and Function anlysis of gene involved in regulation

REGULATION NETWORK OF IRON UPTAKE AND HOMEOSTASIS IN STRATEGY I
PLANTS
Hong-Qing Ling*, Chun l. Chen, Hui l. Wu, Yue Zhang, Ning Wang, Yan Cui.
The State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics
and Developmental Biology, Chinese Academy of Sciences, No. 1 West Beichen Road, Chaoyang District,
Beijing 100101, China
Iron is an essential element. Deficiency and excess of iron will affect plant growth and
development. Its uptake, translocation, internal distribution and utilization are genetically
controlled. The molecular regulation mechanism of iron uptake and homeostasis has been
intensively studied during the past decades. Many genes involved in the regulation process
have been isolated and their functions have been illustrated.
Tomato FER, encoding a bHLH protein, is the first identified regulatory gene involved in the
iron uptake and homeostasis. The ortholog of FER in Arabidopsis is FIT. FIT/FER is a key
gene in the regulation of iron uptake and homeostasis in strategy I plants because loss of
FER/FIT function plants are unable to activate
the typical iron deficiency responses and the
expression of iron uptake genes under iron limitation. In Arabidopsis, FIT interacting with the Ib
subgroup bHLH (Ib bHLH) proteins, which contains bHLH38, bHLH39, bHLH100 and
bHLH101, functioned in the transcriptional activation of iron uptake genes FRO2 and IRT1.
The expression of the four Ib bHLH genes was negatively regulated by SKB1, which as an
epigenetic negative modulator associated with chromatin of the promoters of the four Ib bHLH
genes and mediated their histone H4R3 dimethylation according to iron status of plants. The
four Ib bHLH proteins, possessing functional redundancy, dimerized with FIT. Further, MED16
subunit of the Mediator complex transmits signals to the Pol II complex by associating with FIT
in the FIT/Ib BHLH complex for activating the expression of its regulated genes, such as FRO2
and IRT1. Additionally, it was confirmed that bHLH34 and bHLH104 were involved in iron
uptake and homeostasis in Arabidopsis by controlling the expression of Ib bHLH and PYE
genes. Recently, we also identified other genes functioning in the regulation of FIT expression
and its protein stability. All the researches show that the regulation mechanism of iron uptake
and homeostasis in plants is very complicated and there are many genes involved in the
regulation process. Here, we will present its regulation network by reviewing the progress
obtained recently in strategy I plants, and prospect its future development in this region.
*e-mail address: [email protected]
Key words
Regulation
Iron
Homeostasis
ACKNOWLEDGEMENTS:
This work was supported by National Nature Science Foundation of China (Grant No.
31270294)
Oral
presentation :
Molecular regulation of Fe homeostasis