An Aux/IAA Family Member, RhIAA14, Involved in Ethylene-Inhibited Petal Expansion in Rose (Rosa hybrida)

Abstract

Flower size, a primary agronomic trait in breeding of ornamental plants, is largely determined by petal expansion. Generally, ethylene acts as an inhibitor of petal expansion, but its effect is restricted by unknown developmental cues. In this study, we found that the critical node of ethylene-inhibited petal expansion is between stages 1 and 2 of rose flower opening. To uncover the underlying regulatory mechanism, we carried out a comparative RNA-seq analysis. Differentially expressed genes (DEGs) involved in auxin-signaling pathways were enriched. Therefore, we identified an auxin/indole-3-acetic acid (Aux/IAA) family gene, RhIAA14, whose expression was development-specifically repressed by ethylene. The silencing of RhIAA14 reduced cell expansion, resulting in diminished petal expansion and flower size. In addition, the expressions of cell-expansion-related genes, including RhXTH6, RhCesA2, RhPIP2;1, and RhEXPA8, were significantly downregulated following RhIAA14 silencing. Our results reveal an Aux/IAA that serves as a key player in orchestrating petal expansion and ultimately contributes to flower size, which provides new insights into ethylene-modulated flower opening and the function of the Aux/IAA transcription regulator.

The CALCINEURIN B-LIKE 4/CBL-INTERACTING PROTEIN 3 module degrades repressor JAZ5 during rose petal senescence

“…To identify critical regulatory genes involved in petal senescence, we performed transcriptome sequencing to dissect the transcriptomic changes in rose flowers at 3 stages of development and following treatment with ethylene ( Jia et al 2022 ). We identified differentially expressed genes (DEGs) that were significantly upregulated from Stages 1 to 5 and after ethylene treatment.…”

Genome-wide identification of Aux/IAA and ARF gene families reveal their potential roles in flower opening of Dendrobium officinale

“…contrast, nine genes (DoARF1, 2, 10,16,17,18,21,22,23) displayed a decreasing trend from S1-S3 and exhibited a positive correlation (r > 0.7, p < 0.05) with IAA content. Another nine genes (DoARF7, 8,12,13,14,15,24,25,26) exhibited an unchanged or alternative trend (increasing from S1 to S2, decreasing from S2 to S3…”

“…SlMBP21 , a MADS-box gene involved in the ethylene and auxin pathways, negatively controlled the size of Solanum lycopersicum sepals [ 14 ] . In Rosa hybrida , down-regulation of RhIAA14 by virus-induced gene silencing reduced cell expansion, leading to reduced petal expansion and thus smaller petals [ 16 ]. Moreover, the silencing of RhIAA16 promoted petal abscission [ 17 ].…”