How does the AP2/ERF gene family respond to drought stress?
Foreword: Eucommia ulmoides belongs to the genus Eucommia ulmoides, which is an important economic tree species unique to China with a variety of uses, and the rubber rich in bark, leaves and fruits has the dual property of rubber and plastic, and is the temperate rubber resource with the most development value at present.
Drought is one of the main abiotic stress factors affecting plant growth and development, and has become a worldwide problem restricting the sustainable development of agriculture and forestry industry.
Drought can significantly reduce the photosynthetic efficiency and growth of Eucommia ulmoides, and seriously affect the quality of its economic products, so it is of great practical significance to carry out drought-resistant breeding of Eucommia ulmoides for the directional improvement of Eucommia ulmoides and the selection of excellent varieties for different purposes.
The AP2/ERF family is one of the largest gene families in plants, with one or more AP2 domains, which can specifically bind to GCC-box and DRE-elements in the promoter region, and play an important role in the growth and development of plants and in response to biotic and abiotic stresses.
In this study, a total of 84 AP2/ERF genes were identified in the genome of Eucommia ulmoides, and they were divided into three subfamilies according to the number and variety of conserved domains. It includes the AP2 subfamily (11 genes), the RAV subfamily (2 genes), and the ERF subfamily (71 genes).
Among them, the AP2 subfamily genes usually contain more than two AP2 domains, and the RAV subfamily genes contain one AP2 domain and one B3 domain.
The ERF subfamily contains only one AP2 domain, which can be divided into two subclasses: DREB and ERF, and the rest of the amino acid sequences are classified as the soloist subfamily.
At present, the AP2/ERF gene family has been identified in many species, including 163 in Arabidopsis, 167 in rice, 219 in kiwifruit, 119 in jujube, and 208 in willow.
Compared with other species, the number of AP2/ERF family genes in Eucommia ulmoides was significantly smaller, which may be related to gene replication and evolution in higher plants.
Gene duplication has an important impact on gene family expansion, such as fragment duplication will produce more homologous genes, while tandem duplication
Gene clusters or hot regions of gene distribution may be generated, both of which can increase the number of genes.
In this study, a total of 16 pairs of AP2/ERF paralogous genes were identified in the genome of Eucommia ulmoides, and only 7 pairs of orthologous genes were identified in the two genes of Eucommia ulmoides-Arabidopsis thaliana, and the number of homologous genes was significantly lower than that of other species, indicating that the AP2/ERF gene replication events were few, which hindered the expansion of this gene family.
This may be the reason why the number of AP2/ERF genes in Eucommia ulmoides is lower than that of other species.
Studies have shown that genes in this family play a crucial role in the growth and development of plants, and in response to biotic and abiotic stresses.
Conclusion:
The expression characteristics of genes are affected by the promoter structure and the type of cis-acting elements, and the cis-acting elements are different among different family members, but there are also similarities, indicating that the family members of AP2/ERF transcription factors are functionally differentiated, and different members have synergistic regulatory effects.
The promoter region of Eucommia ulmoides AP2/ERF family members contains a variety of cis-acting elements and a large number of data, which are mainly divided into four categories: stress-responsive elements, hormone responsive elements, light-responsive elements, and growth and development elements.
Most of the EuAP2/ERF genes were rich in cis-acting elements related to drought stress response, indicating that these genes played an important role in the response of Eucommia ulmoides to drought stress.
