Guofan Wu

Highly conserved LOR structural domains are found in proteins encoded by LURP-ONE-RELATED (LOR) family genes, which is named after LATE UP-REGULATED IN RESPONSE TO HYALOPERONOSPORA PARASITICA 1 (LURP1), the first characterized member in Arabidopsis thaliana. Members of the AtLOR gene family play a role in the biotic stress responses in Arabidopsis. In contrast, functional studies on the role of the LOR gene in plant responses to abiotic stresses (such as drought) remain relatively scarce. Using foxtail millet (Setaria italica), a drought-tolerant C4 model plant, this study systematically investigates the LOR gene family. It provides a foundation for improving crop stress tolerance. In this study, forty-two LOR family members were identified via genome-wide analysis of foxtail millet, and phylogenetic tree analysis revealed that the SiLOR gene family could be divided into seven subgroups, which are distributed across six chromosomes of the genome. Furthermore, RNA-Seq data analysis showed that SiLOR genes exhibited differential expression across roots, stems, leaves, and panicles, with the majority predominantly expressed in roots. Cis-acting element analysis indicated that SiLOR genes may be implicated in multiple biological processes, including hormone response, low-temperature response, and dehydration response. The involvement of foxtail millet LOR gene family members in abiotic stress was strongly supported by RNA-Seq and quantitative real-time PCR (qRT-PCR) results, which confirmed their drought stress-induced expression and demonstrated that SiLOR3, SiLOR11, SiLOR12, SiLOR16, and SiLOR18 were significantly upregulated. Collectively, this study provides vital starting points for further investigation into the functional roles of SiLOR genes in foxtail millet.

Winter rapeseed (Brassica rapa) has a good chilling and freezing tolerance. inducer of CBF expression 1 (ICE1) plays a crucial role in cold signaling in plants; however, its role in Brassica rapa remains unclear. In this study, we identified 41 ICE1 homologous genes from six widely cultivated Brassica species. These genes exhibited high conservation, with evolutionary complexity between diploid and allotetraploid species. Cold stress induced ICE1 homolog expression, with differences between strongly and weakly cold-tolerant varieties. Two novel ICE1 paralogs, BrICE1 and BrICE2, were cloned from Brassica rapa Longyou 6. Subcellular localization assays showed that they localized to the nucleus, and low temperature did not affect their nuclear localization. The overexpression of BrICE1 and BrICE2 increased cold tolerance in transgenic Arabidopsis and enhanced reactive oxygen species’ (ROS) scavenging ability. Furthermore, our data demonstrate that overexpression of BrICE1 and BrICE2 inhibited root growth in Arabidopsis, and low temperatures could induce the degradation of BrICE1 and BrICE2 via the 26S-proteasome pathway. In summary, ICE1 homologous genes exhibit complex evolutionary relationships in Brassica species and are involved in the C-repeat/DREB binding factor (CBF) pathway and ROS scavenging mechanism in response to cold stress; these regulating mechanisms might also be responsible for balancing the development and cold defense of Brassica rapa.

Winter rapeseed (Brassica rapa) has good chilling and freezing tolerance. INDUCER OF CBF EXPRESSION1 (ICE) plays a crucial role in cold signaling in plant; however, its role in B. rapa remains unclear. In this study, we identified 41 ICE1 homologous genes from 6 widely cultivated Brassica species. These genes exhibited high conservation, with evolutionary complexity between diploid and allotetraploid species. Cold stress induced ICE1 homolog expression, with differences between strong and weak cold-tolerant varieties. Two novel ICE1 paralogs, BrICE1 and BrICE2 were cloned from B. rapa Longyou 6. Subcellular localization assays showed that they localized to the nucleus, and low temperature did not affect their nuclear localization. Overexpression of BrICE1 and BrICE2 increased cold tolerance in transgenic Arabidopsis, and enhanced reactive oxygen species (ROS) scavenging ability. Furthermore, our data demonstrate that overexpression of BrICE1 and BrICE2 inhibited root growth in Arabidopsis, and low temperatures could induce the degradation of BrICE1 and BrICE2 via the 26S-proteasome pathway. In summary, ICE1 ho-mologous genes exhibit complex evolutionary relationships in Brassica species, and are involved in the CBF pathway, and ROS scavenging mechanism in response to cold stress; these regulating mechanisms might be also responsible for balancing the development and cold defense of B. rapa.

Inducer of C-Repeat Binding Factor (CBF) expression (ICE), a well-known MYC-type bHLH transcription factor, plays a crucial role in the ICE-CBF-cold regulated (COR) cold signaling pathway. Brassica rapa (B. rapa), an important oilseed and vegetable crop, exhibits strong chilling and freezing tolerance. However, the exact molecular mechanisms by which ICE1 functions in B. rapa remain unclear. Here, 41 ICE1 homologous genes were identified from six widely cultivated Brassica species using a bioinformatics approach. These genes exhibit high conservation but reveal evolutionary complexity between diploid and allotetraploid species. Low-temperature stress induced ICE1 homolog expression, with patterns differing between strong and weak cold-tolerant varieties. Two novel ICE1 paralogs, BrICE1 and BrICE2, were cloned from Longyou 6. They positively regulate cold tolerance in B. rapa via a CBF-dependent pathway, contributing to reactive oxygen species (ROS) scavenfging and osmotic adjustment. Immunoblot analysis revealed that low temperatures induce BrICE1 and BrICE2 degradation via the 26S-proteasome pathway. In summary, ICE1 exhibits complex evolutionary relationships in Brassica species. BrICE1 and BrICE2 positively regulate cold tolerance via the CBF-dependent pathway and ROS scavenging mechanism and are also responsible for balancing the development and cold defense of B. rapa.

The MYB (v-Myb avivan myoblastsis virus oncogene homolog) transcription factor family is one of the largest families of plant transcription factors which plays a vital role in many aspects of plant growth and development. MYB-related is a subclass of the MYB family. Fifty-nine Arabidopsis thaliana MYB-related (AtMYB-related) genes have been identified. In order to understand the functions of these genes, in this review, the promoters of AtMYB-related genes were analyzed by means of bioinformatics, and the progress of research into the functions of these genes has been described. The main functions of these AtMYB-related genes are light response and circadian rhythm regulation, root hair and trichome development, telomere DNA binding, and hormone response. From an analysis of cis-acting elements, it was found that the promoters of these genes contained light-responsive elements and plant hormone response elements. Most genes contained elements related to drought, low temperature, and defense and stress responses. These analyses suggest that AtMYB-related genes may be involved in A. thaliana growth and development, and environmental adaptation through plant hormone pathways. However, the functions of many genes do not occur independently but instead interact with each other through different pathways. In the future, the study of the role of the gene in different pathways will be conducive to a comprehensive understanding of the function of the gene. Therefore, gene cloning and protein functional analyses can be subsequently used to understand the regulatory mechanisms of AtMYB-related genes in the interaction of multiple signal pathways. This review provides theoretical guidance for the follow-up study of plant MYB-related genes.

Foxtail millet (Setaria italica) would be suitable as a model plant of C4 plants given its small genome (about 470 MB) and diploid self-pollination. However, the study of foxtail millet faces the problem of low efficiency of explant regeneration and genetic transformation. In this study, a new genetic transformation system of Yugu1 foxtail millet is established with in vitro shoot tips as the explant, and, the concentrations of 6-BA and kanamycin are optimized. It is found 0.5 mg L-1 6-BA and 25 mg L-1 kanamycin are the most suitable in terms of the differentiation rate of shoot tips and survival rate of differentiated seedlings. In addition, 12 transgenic foxtail millets of SiSERK1 are identified by resistance screening and PCR. The insertion site of one line of the transgenic plants chosen at random is further identified. The results of qRT-PCR show that the expression of SiSERK1 gene in transgenic plants is significantly higher than that in wild-type plants. A new method of generation of material for further study of SiSERKs is provided for foxtail millet genetics and breeding.

Early Responsive to Dehydration (ERD) genes are rapidly induced in response to various biotic and abiotic stresses, such as bacteria, drought, light, temperature and high salt in Arabidopsis thaliana. Sixteen ERD of Arabidopsis thaliana (AtERD) genes have been previously identified. The lengths of the coding region of the genes are 504–2838 bp. They encode 137–745 amino acids. In this study, the AtERD genes structure and promoter are analyzed through bioinformatics, and a overall function is summarized and a systematic signal pathway involving AtERD genes is mapped. AtERD9, AtERD11 and AtERD13 have the GST domain. AtERD10 and AtERD14 have the Dehyd domain. The promoters regions contain 32 light responsive elements, 23 ABA responsive elements, 5 drought responsive elements, 5 meristem expression related elements and 132 core promoter elements. The study provides a theoretical guidance for subsequent studies of AtERD genes.