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Scientia Silvae Sinicae ›› 2025, Vol. 61 ›› Issue (5): 146-160.doi: 10.11707/j.1001-7488.LYKX20240323

• Research papers • Previous Articles     Next Articles

Analysis of Purple Acid Phosphatases Genes (PAPs) Family in Phoebe bournei and the Functions of Three PAPs under Low Phosphorus Stress

Yiman Zhang,Longjun Lu,Yuting Zhang,Qi Yang,Xiao Han,Zaikang Tong,Junhong Zhang*()   

  1. State Key Laboratory of Subtropical Silviculture Zhejiang A & F University Hangzhou 311300
  • Received:2024-06-03 Online:2025-05-20 Published:2025-05-24
  • Contact: Junhong Zhang E-mail:zhangjunhong@zafu.edu.cn

Abstract:

Objective: Phoebe bournei is well adapted in red soils with low available phosphorus. Purple acid phosphatases (PAPs) are important acid phosphatases that hydrolyse a wide range of substrates in response to low phosphorus stress to release soluble inorganic phosphorus. This study aims to identify PAPs genes in response to low phosphorus stress and verify the functions in order to explore the response mechanism of P. bournei under low phosphorus stress, which will provide a theoretical basis for cultivating germplasm with efficient phosphorus utilization in P. bournei. Method: Based on the genome data of P. bournei, the PAPs gene family was identified by blastp homology and hmmersearch, and the protein sequences of PbPAPs were compared with those of Arabidopsis thaliana and Picea abies to construct a phylogenetic tree. The photosynthetic fluorescence parameters, inorganic phosphorus content, acid phosphatase (ACP) activity and the expression levels of PbPAPs under different phosphorus contents (0 mmol·L?1 KH2PO4 and 1 mmol·L?1 KH2PO4) in two P. bournei families (Jing'an No.3 and Yifeng No.5) were analyzed, and then three PbPAPs were screened out for the subsequent functional study. Result: A total of 22 PbPAPs genes were identified, all contained Metallophos domains, and were unevenly distributed on 10 chromosomes of P. bournei, with amino acid lengths ranging from 326 to 648 aa. Most of PbPAPs proteins had isoelectric points less than 7, and the exons number ranged from 2 to 13. These PbPAPs harbored two pairs of tandem duplications and four pairs of segmental duplications, and the phylogenetic tree was divided into 3 groups. Under low phosphorus treatments, the elongation of the primary root was inhibited, while the root hair density and the surface area of the root system were increased in the seedlings of P. bournei two families. The net photosynthetic rate and Fv/Fm value were decreased significantly, while the acid phosphatase activity increased. The inorganic phosphorus content of Jing'an No.3 leaves firstly declined and then increased slightly, while the change in Yifeng No.5 was relatively stable. A significant decrease of Pi content was observed in the Jing'an No.3 root after 7 days of treatment, while a significant decrease was firstly observed in the Yifeng No.5 after 21 days of treatment, and the change trends in the later stage of treatments were similar. According to RT-qPCR analysis, low phosphorus induced the gene expression level of PbPAP10a, PbPAP15a and PbPAP26. The three genes of PbPAP10a, PbPAP15a and PbPAP26 were overexpressed in P. bournei roots and A. thaliana by Agrobacterium tumefaciens- and A. rhizocarcinosum-mediated genetic transformation, which resulted in a significant enhancement of ACP activity and a significant increase in Pi content. Thus, overexpression of the PbPAPs gene increased ACP activity and Pi content. Conclusion: It is shown that P. bournei has high tolerance to low phosphorus stress, and Yifeng No.5 is more tolerant to low phosphorus stress than that of Jing'an No.3, which is suitable for forestation in barren forest land or acidic low phosphorus forest land. Overexpression of PbPAPs gene increases ACP activity and Pi content, which would help P. bournei to adapt to the low phosphorus environments.

Key words: Phoebe bournei, purple acid phosphatase, low phosphorus stress, gene family, Pi content

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