Jasmonates—the Master Regulator of Rice Development, Adaptation and Defense

Rice is one of the most important food crops worldwide, as well as the model plant in molecular studies on the cereals group. Many different biotic and abiotic agents often limit rice production and threaten food security. Understanding the molecular mechanism, by which the rice plant reacts and resists these constraints, is the key to improving rice production to meet the demand of an increasing population. The phytohormone jasmonic acid (JA) and related compounds, collectively called jasmonates, are key regulators in plant growth and development. They are also one of the central players in plant immunity against biotic attacks and adaptation to unfavorable environmental conditions. Here, we review the most recent knowledge about jasmonates signaling in the rice crop model. We highlight the functions of jasmonates signaling in many adaptive responses, and also in rice growth and development processes. We also draw special attention to different signaling modules that are controlled by jasmonates in rice.


JA biosynthesis
The pre/cpm1 plant has long leaves and elongated coleoptiles and mesocotyls, flowers approximately 5 days earlier with the flowers remaining open after flowering, and is partially sterile.

JA biosynthesis
The mutation in OsOPR7 results in the lemma and palea not being able to fully close during anthesis and malformed, shriveled, and mildewed seeds within open glumes. [34,35]

OsJAR1 osjar1
Os05g0586200 Catalyzes the conjugation of JA and an amino acid Loss of function of OsJAR1 and defects in husk closure and anther dehiscence. [36]

OsCYP94C2b CYP94C2b_OE Os12g0150200
Catalyzes the conversion of JA-Ile into 12-OH-JA-Ile and 12-COOH-JA-Ile Increases salt tolerance and increases internode length and plant height under normal conditions when overexpressed. [106,107]

Repressor in JA signaling
Increases floret number, culm length, and grain weight; reduces heading time and spikelet fertility; and enhances root growth when overexpressed.

Repressor in JA signaling
Increased number of organs in florets, aberrant patterns of organ formation, and repetitious organ production in spikelets when overexpressed in the dominant negative form. [44]

Repressor in JA signaling
Increased floret number, culm length, and grain weight and reduced heading time and spikelet fertility when overexpressed. [45]

Repressor in JA signaling
Increased floret number, culm length, and grain weight and reduced heading time and spikelet fertility when overexpressed.
Increased number of organs in florets, aberrant patterns of organ formation, and repetitious organ production in spikelets when overexpressed in the dominant negative form. [44,45]

Repressor in JA signaling
Increased floret number, culm length, grain weight, and heading time when overexpressed.
Increased number of organs in florets, aberrant patterns of organ formation, and repetitious organ production in spikelets when overexpressed in the dominant negative form. [44,45]

Repressor in JA signaling
Increased floret number and culm length; reduced heading time, spikelet fertility, and grain weight when overexpressed.
Insensitive to JA treatment and loses JA-induced resistance to Xanthomonas oryzae pv oryzae when overexpressed in the dominant negative form. [45,57] OsJAZ9 OsJAZ9_OE osjaz9 Os03g0180800

Repressor in JA signaling
Increased floret number, culm length, and grain weight; reduced heading time and spikelet fertility and increased salt tolerance when overexpressed.

Repressor in JA signaling
Increased floret number, culm length, and grain weight; reduced heading time and spikelet fertility when overexpressed. [45]

Repressor in JA signaling
Increased floret number, culm length, and grain weight; a reduced number of days to flowering and spikelet fertility when overexpressed. [44,45] Increased number of organs in florets, aberrant patterns of organ formation, and repetitious organ production in spikelets when overexpressed in the dominant negative form.

Repressor in JA signaling
Increased floret number, culm length, and grain weight; reduced number of days to flowering and spikelet fertility when overexpressed. [45]

Repressor in JA signaling
Increased floret number; reduced number of days to flowering, grain weight, culm length, and spikelet fertility when overexpressed. [45] OsCOI1a oscoi1aRNAi Os01g0853400

Receptor of JA-Ile
Increased plant height and grain length and increased susceptibility to the rice leaf folder (LF) Cnaphalocrocis medinalis and the Rice black streaked dwarf virus (RBSDV) when silenced.

Receptor of JA-Ile
Delays leaf senescence and reduces fertility and grain filling rate when mutated.

Increases plant height and grain length and increases susceptibility to the Rice black streaked dwarf virus
(RBSDV) when silenced. [39,40,75]

Component of a corepressor complex and connects JAZ and NINJA proteins in JA signaling
Increases susceptibility to the bacterial blight disease caused by Xanthomonas oryzae pv oryzae, and delays leaf senescence when overexpressed. [47] OsMYC2 OsMYC2_OE osmyc2RNAi Os10g0575000

Activator of a transcription factor in JA signaling
Regulates senescence-associated genes, inhibits seedling growth, and increases resistance to Xanthomonas oryzae pv oryzae when overexpressed.
Reduces expression of JA-responsive genes when silenced.

OsRSS3 rss3 (rice salt sensitive 3) Os11g0446000
RSS3's function is required for root cell elongation and the control of root growth under salinity conditions. A loss of function of RSS3 moderately inhibits cell elongation under normal conditions, but it provokes spontaneous root cell swelling, accompanied by severe root growth inhibition, under saline conditions. [1056]