Dynamic Regulation of Auxin Response during Rice Development Revealed by Newly Established Hormone Biosensor Markers.
The hormone auxin is critical for many plant developmental processes. Unlike the model eudicot plantArabidopsis(Arabidopsis thaliana), auxin distribution and signaling in rice tissues has not been systematically investigated due to the absence of suitable auxin response reporters. In this study we observed the conservation of auxin signaling components betweenArabidopsisand model monocot crop rice (Oryza sativa), and generated complementary types of auxin biosensor constructs, one derived from the Aux/IAA-based biosensorDII-VENUSbut constitutively driven by maize ubiquitin-1 promoter, and the other termedDR5-VENUS in which a synthetic auxin-responsive promoter (DR5rev) was used to drive expression of the yellow fluorescent protein (YFP). Using the obtained transgenic lines, we observed that during the vegetative development, accumulation ofDR5-VENUS signal was at young and mature leaves, tiller buds and stem base. Notably, abundantDR5-VENUS signals were observed in the cytoplasm of cortex cells surrounding lateral root primordia (LRP) in rice. In addition, auxin maxima and dynamic re-localization were seen at the initiation sites of inflorescence and spikelet primordia including branch meristems (BMs), female and male organs. The comparison of these observations amongArabidopsis, rice and maize suggests the unique role of auxin in regulating rice lateral root emergence and reproduction. Moreover, protein localization of auxin transporters PIN1 homologs and GFP tagged OsAUX1 overlapped withDR5-VENUS during spikelet development, helping validate these auxin response reporters are reliable markers in rice. This work firstly reveals the direct correspondence between auxin distribution and rice reproductive and root development at tissue and cellular level, and provides high-resolution auxin tools to probe fundamental developmental processes in rice and to establish links between auxin, development and agronomical traits like yield or root architecture.
Key Laboratory of Systems Biomedicine, Ministry of Education, Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong UniversityShanghai, China; Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong UniversityShanghai, China.
Jing
J
Yang
Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai, China.
Zheng
Z
Yuan
Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai, China.
Qingcai
Q
Meng
Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai, China.
Guoqiang
G
Huang
CIRAD, UMR AGAP Montpellier, France.
Christophe
C
Périn
CIRAD, UMR AGAP Montpellier, France.
Charlotte
C
Bureau
CIRAD, UMR AGAP Montpellier, France.
Anne-Cécile
AC
Meunier
CIRAD, UMR AGAP Montpellier, France.
Mathieu
M
Ingouff
Centre for Plant Integrative Biology, School of Biosciences, University of Nottingham Sutton Bonington, UK.
Malcolm J
MJ
Bennett
Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai, China.
Wanqi
W
Liang
Joint International Research Laboratory of Metabolic & Developmental Sciences, Shanghai Jiao Tong University-University of Adelaide Joint Centre for Agriculture and Health, School of Life Sciences and Biotechnology, Shanghai Jiao Tong UniversityShanghai, China; School of Agriculture, Food and Wine, University of AdelaideUrrbrae, SA, Australia.
Dabing
D
Zhang
auxin; inflorescence; lateral root formation; meristem; reporter; rice; spikelet