Cloning, Characterization and Expression Analysis of the Phosphate Starvation Response Gene, ClPHR1, from Chinese Fir

Abstract

The study on the function and sequence of PHR1 (Phosphate Starvation Response gene 1) gene, which plays a central role in plant phosphorus (Pi) signal regulatory network, is of great significance to further study response mechanisms to Pi deficiency. In this work, the previously selected Pi-efficient Chinese fir clone M32 was used as research material to obtain the full-length sequence of ClPHR1 transcription factors in Chinese fir by RACE (Rapid Amplification of cDNA Ends) full-length cloning technique, and the structure, function and subcellular localization of ClPHR1 gene encoding protein were analyzed. The temporal and spatial expression characteristics of ClPHR1 transcription factors in Chinese fir under low Pi stress were also analyzed, and the overexpression of ClPHR1 gene in transgenic Arabidopsis thaliana was obtained to verify the function of ClPHR1 gene under low Pi stress. The results showed that the length of the ClPHR1 gene obtained by rapid amplification of cDNA ends technique was 1954 bp, of which 1512 bp was an open reading frame. ClPHR1 was predicted to be an unstable hydrophilic protein with only one possible transmembrane domain. The ClPHR1 gene had a highly conserved MYB-CC domain, which is similar to the PHR1 gene of other plants. Phylogenetic tree analysis showed that the sequence had high homology with PHR1 genes in the Prunus species. The ClPHR1 was expressed in all organs of Chinese fir, with the highest expression in the roots, followed by the leaves with the lowest expression in stems. ClPHR1 expression in roots was reduced dramatically at the beginning of Pi stress treatment and followed by an increase at 7days; in leaves, it increased dramatically at the beginning of Pi starvation treatment and showed a decreasing trend after 3 days; in stems, the expression level of ClPHR1 increased after 7 days of Pi stress treatment. The transient expression vector was introduced into plant cells, and it was found that ClPHR1 was located in the nucleus and was a MYB-CC transcription factor expressed in the cell nucleus. The ClPHR1 overexpression vector was constructed, and then introduced into Arabidopsis thaliana by agrobacterium infection inflorescence method. The expressions of Pi transporter genes, AtPHT1;1, AtPHT1;2, AtPHT1;8 and AtPHT1;9, was significantly higher in the overexpressing strain than that in the wild type strain. The results suggest that the ClPHR1 transcription factor could regulate the regulation of downstream Pi transporter gene and increase Pi utilization efficiency of the Chinese fir under Pi stress.

Transcriptome-Wide Identification and Expression Profiling of SPX Domain-Containing Members in Responses to Phosphorus Deprivation of Pinus massoniana

“…massoniana materials and Pi stress treatments were similar to previous research [36]. The plants were grown in perlite in an illuminated incubator with a cycle of 14 h/25 [40]. The phosphorus concentration in the treated nutrient solution was adjusted by KH 2 PO 4 .…”

Comparative Transcriptome Analysis Reveals Key Genes and Pathways Associated with Phosphate-Sensitive Behaviors in Cunninghamia lanceolata (Lamb.) Hook.

“…Strikingly, plants have evolved a range of morphological, physiological, and biochemical adaptation mechanisms (e.g., alteration of root architecture, interaction with symbiotic mycorrhizal fungi, secretion of organic acid anions, increased expression of phosphorus transporters, and changes in metabolic processes) to enhance the acquisition of Pi [4][5][6]. Because of soil phosphorus enrichment and water pollution caused by traditional fertilization methods, as well as the non-renewable nature of phosphorus resources, it has become one of the hot spots of global research to study the mechanism of high-efficiency absorption Pi of plants to excavate the genotype of high-efficiency Pi utilization [4][5][6][7][8][9]. Numerous studies on crops and trees, such as Zea mays (maize) [10], Lycopersicon esculentum (tomato) [11], Camellia oleifera [12], and Pinus massoniana [13], have shown that there are significant genotypic differences in the uptake, transport, and utilization efficiency of soil phosphorus among different species or different varieties of the same species.…”

“…(Chinese fir) is one of the most important commercial timber and afforestation species in southern China [14]. However, the low level of active Pi in the acidic soil of southern forest lands and continuous replanting on the same sites are important factors to restrict the long-term productivity of Chinese fir plantations [9]. Previous studies have shown that Pi-deficiency stress had a significant influence on biomass accumulation and distribution pattern, root system architecture, acid phosphatase activity, endogenous hormone content, and protein expression in Chinese fir [9,[15][16][17].…”