|YANG, LIMING - Huaiyin Normal University|
|JI, JIANHUI - University Of Georgia|
|ABD_ALLAH, E - Chinese Academy Of Sciences|
|HU, YIANGYANG - King Saud University|
|GUAN, YANLONG - King Saud University|
Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/2016
Publication Date: 3/7/2016
Citation: Yang, L., Ji, J., Wang, H., Harris-Shultz, K.R., Abd_Allah, E.F., Hu, Y., Guan, Y. 2016. Carbon monoxide interacts with auxin and nitric oxide to cope with iron deficiency in Arabidopsis. Frontiers in Plant Science. 7:112.
Interpretive Summary: Iron deficiency severely limits yield for crops grown in calcareous soils. Many of the genes involved in iron uptake have been characterized in Arabidopsis but the signaling pathway involved during iron deficiency remains to be fully characterized. In this study, the roles of carbon monoxide, nitric acid, and auxin were examined for Arabidopsis root tips during iron deficiency. Iron deficiency increases carbon monoxide, nitric oxide, and auxin accumulation in root tips. Using a series of mutants, double mutants, chemical treatments, and various biochemical assays, we discovered that during iron deficiency auxin, carbon dioxide, and nitric oxide all form an integrative signaling pathway that reduce the effects of iron deficiency.
Technical Abstract: To clarify the roles of CO, NO and auxin in the plant response to iron deficiency and to establish how the signaling molecules interact to enhance Fe acquisition, we conducted physiological, genetic, and molecular analyses that compared the responses of various Arabidopsis mutants, including hy1 (CO deficient), noa1 (NO deficient), nia1/nia2 (NO deficient), yuc1 (auxin over-accumulation), and cue1 (NO over-accumulation) during iron deficiency. We also generated a HY1 over-expression line (named HY1-OX) in which CO is over-produced compared to wild-type. We found that the suppression of CO and NO generation using various inhibitors enhanced the sensitivity of wild-type plants to Fe depletion. Similarly, the hy1, noa1, and nia1/nia2 mutants were more sensitive to Fe deficiency. By contrast, the yuc1, cue1, and HY1-OX lines were less sensitive to Fe depletion. The hy1 mutant with low CO content exhibited no induced expression of the Fe uptake-related genes FIT1 and FRO2 as compared to wild-type plants. On the other hand, the treatments of exogenous CO and NO enhanced Fe uptake. Likewise, cue1 and HY1-OX lines with increased endogenous content of NO and CO, respectively, also exhibited enhanced Fe uptake and increased expression of the bHLH transcriptional factor FIT1as compared to wild-type plants. Furthermore, we found that CO affected auxin accumulation and transport in the root tip by altering the PIN1 and PIN2 protein distributions that control the lateral root structure under iron deficiency stress. Our results demonstrated the integration of CO, NO and auxin signaling to cope with Fe deficiency in Arabidopsis.