Abdul Azeez1, Pál Miskolczi1, Szymon Tylewicz1, Rishikesh P Bhalerao2. 1. Umeå Plant Science Center, Department of Forest Genetics and Plant Physiology, SLU, 90187 Umeå, Sweden. 2. Umeå Plant Science Center, Department of Forest Genetics and Plant Physiology, SLU, 90187 Umeå, Sweden. Electronic address: rishi.bhalerao@slu.se.
Abstract
BACKGROUND: Photoperiodic control of development plays a key role in adaptation of plants to seasonal changes. A signaling module consisting of CONSTANS (CO) and FLOWERING LOCUS T (FT) mediates in photoperiodic control of a variety of developmental transitions (e.g., flowering, tuberization, and seasonal growth cessation in trees). How this conserved CO/FT module can mediate in the photoperiodic control of diverse unrelated developmental programs is poorly understood. RESULTS: We show that Like-AP1 (LAP1), a tree ortholog of Arabidopsis floral meristem identity gene APETALA1 (AP1), mediates in photoperiodic control of seasonal growth cessation downstream of the CO/FT module in hybrid aspen. Using LAP1 overexpressors and RNAi-suppressed transgenic trees, we demonstrate that short day (SD)-mediated downregulation of LAP1 expression is required for growth cessation. In contrast with AP1 targets in flowering, LAP1 acts on AINTEGUMENTA-like 1 transcription factor, which is implicated in SD-mediated growth cessation. Intriguingly, unlike AP1 in Arabidopsis, ectopic expression of LAP1 fails to induce early flowering in hybrid aspen trees. CONCLUSIONS: These results indicate that AP1 ortholog in trees has acquired a novel function in photoperiodic regulation of seasonal growth. Thus, photoperiodic signaling pathway may have diverged downstream of AP1/LAP1 rather than the CO/FT module during evolution. Moreover, control of flowering by the CO/FT module can be uncoupled from its role in photoperiodic control of seasonal growth in trees. Thus, our findings can explain mechanistically how a conserved signaling module can mediate in the control of a highly diverse set of developmental transitions by a similar input signal, namely photoperiod.
BACKGROUND: Photoperiodic control of development plays a key role in adaptation of plants to seasonal changes. A signaling module consisting of CONSTANS (CO) and FLOWERING LOCUS T (FT) mediates in photoperiodic control of a variety of developmental transitions (e.g., flowering, tuberization, and seasonal growth cessation in trees). How this conserved CO/FT module can mediate in the photoperiodic control of diverse unrelated developmental programs is poorly understood. RESULTS: We show that Like-AP1 (LAP1), a tree ortholog of Arabidopsis floral meristem identity gene APETALA1 (AP1), mediates in photoperiodic control of seasonal growth cessation downstream of the CO/FT module in hybrid aspen. Using LAP1 overexpressors and RNAi-suppressed transgenic trees, we demonstrate that short day (SD)-mediated downregulation of LAP1 expression is required for growth cessation. In contrast with AP1 targets in flowering, LAP1 acts on AINTEGUMENTA-like 1 transcription factor, which is implicated in SD-mediated growth cessation. Intriguingly, unlike AP1 in Arabidopsis, ectopic expression of LAP1 fails to induce early flowering in hybrid aspen trees. CONCLUSIONS: These results indicate that AP1 ortholog in trees has acquired a novel function in photoperiodic regulation of seasonal growth. Thus, photoperiodic signaling pathway may have diverged downstream of AP1/LAP1 rather than the CO/FT module during evolution. Moreover, control of flowering by the CO/FT module can be uncoupled from its role in photoperiodic control of seasonal growth in trees. Thus, our findings can explain mechanistically how a conserved signaling module can mediate in the control of a highly diverse set of developmental transitions by a similar input signal, namely photoperiod.
Authors: Héloïse Bastiaanse; Matthew Zinkgraf; Courtney Canning; Helen Tsai; Meric Lieberman; Luca Comai; Isabelle Henry; Andrew Groover Journal: Proc Natl Acad Sci U S A Date: 2019-06-18 Impact factor: 11.205
Authors: Jay P Maurya; Pal C Miskolczi; Sanatkumar Mishra; Rajesh Kumar Singh; Rishikesh P Bhalerao Journal: Proc Natl Acad Sci U S A Date: 2020-05-11 Impact factor: 11.205
Authors: Szymon Tylewicz; Hiroyuki Tsuji; Pál Miskolczi; Anna Petterle; Abdul Azeez; Kristoffer Jonsson; Ko Shimamoto; Rishikesh P Bhalerao Journal: Proc Natl Acad Sci U S A Date: 2015-02-23 Impact factor: 11.205