Biology subjects

Xiang, C.

Publications and source records attributed to Xiang, C..

3 recordsLinked to original sources

bioRxiv2018

Arabidopsis HB52 mediates the crosstalk between ethylene and auxin signaling pathways by regulating PIN2, WAG1, and WAG2 during primary root elongation

The gaseous hormone ethylene participates in many physiological processes of plants. It is well known that ethylene-inhibited root elongation involves basipetal auxin delivery requiring PIN2. However, the molecular mechanism how ethylene regulates PIN2 is not well understood. Here, we report that the ethylene-responsive HD-Zip gene HB52 is involved in ethylene-mediated inhibition of primary root elongation. Using biochemical and genetic analyses, we demonstrated that HB52 is ethylene-responsive and acts immediately downstream of EIN3. HB52 knock-down mutants are insensitive to ethylene in primary root elongation while the overexpression lines have dramatically shortened roots like ethylene treated plants. Moreover, HB52 upregulates PIN2, WAG1, and WAG2 by directly binding to their promoter, leading to an enhanced basipetal auxin delivery to the elongation zone and thus inhibiting root growth. Our work uncovers HB52 as an important crosstalk node between ethylene signaling and auxin transport in root elongation.

plant biology↗

bioRxiv2017

A Genetic Pathway Composed of EDT1/HDG11, ERECTA, and E2Fa Loci Regulates Water Use Efficiency by Modulating Stomatal Density

Improvement of crop drought resistance and water use efficiency (WUE) has been a major endeavor in agriculture. ERECTA is the first identified major effector of water use efficiency. However, the underlying molecular mechanism is not well understood. Here, we report a genetic pathway, composed of EDT1/HDG11, ERECTA, and E2Fa loci, which regulates water use efficiency by modulating stomatal density. The HD-START transcription factor EDT1/HDG11 transcriptionally activates ERECTA expression by binding to an HD cis-element in the ERECTA promoter. ERECTA in turn relies on E2Fa to control the expression of cell-cycle related genes and the transition from mitosis to endocycle, which leads to increased nuclear DNA content in leaf cells, and therefore increased cell size and decreased stomatal density. The decreased stomatal density improves plant WUE. Our study demonstrates the EDT1/HDG11-ERECTA-E2Fa genetic pathway that reduces stomatal density by increasing cell size, providing a new avenue to improve WUE of crops.

plant biology↗

bioRxiv2016

Arabidopsis MADS-box transcription factor AGL21 acts as environmental surveillance for seed germination by regulating ABI5

Seed germination is a crucial checkpoint for plant survival under unfavorable environmental conditions. Abscisic acid (ABA) and its signaling play a vital role in integrating environmental information to regulate seed germination. MCM1/AGAMOUS/DEFICIENS/SRF (MADS)-box transcription factors are mainly known as key regulators of seed and flower development in Arabidopsis. However, their functions in seed germination are still poorly understood. Here we report that MADS-box transcription factor AGL21 negatively modulates seed germination and post-germination growth by controlling the expression of ABA-INSENSITIVE 5 (ABI5) in Arabidopsis. AGL21 responds to multiple environmental stresses and plant hormones. The AGL21-overexpressing plants are hypersensitive to ABA, salt and osmotic stresses during seed germination and early post-germination growth, whereas agl21 mutants are less sensitive. AGL21 positively regulates ABI5 expression in seeds. Genetic analyses reveal that AGL21 is epistatic to ABI5 in controlling seed germination. Chromatin immunoprecipitation assays further demonstrate that AGL21 could directly bind to the ABI5 promoter in plant cells. Taken together, our results suggest that AGL21 acts as a surveillance integrator that incorporates environmental cues and endogenous hormonal signals into ABA signaling to regulate seed germination and early post-germination growth.

plant biology↗