Abstract：Phoebe bournei is a precious tree spiece unique to China. Afforestation in red loam which is very popular in south of China is prone to low phosphorus stress, affecting cultivation benefit. Exploring the gene resources in P. bournei with phosphorus tolerance is of great significance to develop P. bournei varieties with enhancing ability of low phosphorus tolerance by molecular assisted breeding. SPX gene is associated with phosphorus absorption and balance in plants. In this study, members of the SPX gene family in P. bournei were identified in the whole genome, and the expression of PbSPX gene in the roots, stems, and leaves of P. bournei were analyzed using qPCR, as well as the expression patterns in the roots and leaves of P. bournei after 10 and 60 d of phosphorus deficiency treatment. The results showed that 20 PbSPXs were distributed on chromosomes 1 to 10 of P. bournei. According to characteristics of protein and phylogenetic tree, PbSPXs were divided into 4 subfamilies, including 6 members of SPX subfamily, 7 members of SPX-EXS subfamily, 3 members of SPX-MFS subfamily and 4 members of SPX-RING subfamily. Analysis of promoter cis-acting elements showed that PbSPX genes containing elements related to phosphorus stress response, such as P1BS, W-box and MBS. Tissue specific expression analysis showed that PbSPX2, PbSPX-EXS1 and PbSPX-RING2 were mainly expressed in roots, and another 12 PbSPXs were expressed highly in leaves. In roots, when treated with phosphorus deficiency after 10 and 60 d, the expression of PbSPX-MFS1 and all PbSPX subfamily members except for PbSPX6 were induced and the expression of them were significantly up-regulated compared to the control, however, the expression of PbSPX-MFS2 was significantly down-regulated. At the same time, the transcript levels of PbSPX-RING1 and PbSPX-EXS1 were significantly increased at 10 d of phosphorus deficiency treatment, while the expressions of PbSPX-RING3 and PbSPX-EXS2 were significantly up-regulated until after 60 d of phosphorus deficiency treatment. The expression of PbSPX-EXS6 was significantly decreased when treated with phosphorus deficient for 10 d, whereas it was significantly up-regulated after 60 d of phosphorus deficiency treatment. In leaves, the expressions of PbSPX1~5, PbSPX-EXS1 and PbSPX-MFS1 were induced after 60 d of phosphorus deficiency treatments, and their expressions were significantly up-regulated compared to the control. The transcript level of PbSPX-MFS2 was significantly down-regulated after 60 d of phosphorus deficiency treatment, which was consistent with the expression trend in roots. As phosphorus transporters candidates, PbSPX-EXS1, PbSPX-EXS2 and PbSPX-EXS6 responded differently to phosphorus level signals in different tissues. The results showed that members of the SPX subfamily of P. bournei were involved in phosphorus stress response, and their expression was regulated by phosphorus levels in different tissues. This study revealed the relationship between PbSPX genes and the response of low phosphorus stress in P. bournei, providing a reference for exploiting key gene resources of low phosphorus tolerance in P. bournei and further studying function and mechanism of PbSPX.
吴梦洁, 洪家都, 李芳燕, 周生财, 程龙军. 闽楠SPX基因家族的鉴定及其缺磷胁迫下的表达分析[J]. 农业生物技术学报, 2023, 31(9): 1832-1845.
WU Meng-Jie, HONG Jia-Du, LI Fang-Yan, ZHOU Sheng-Cai, CHENG Long-Jun. Identification of SPX Gene Family in Phoebe bournei and Its Expression Analysis Under Phosphorus Deficiency Stress. 农业生物技术学报, 2023, 31(9): 1832-1845.
[1] 孙超, 廖德华, 吴双. 2021. 植物SPX-PHR模块在营养信号途径中的作用研究进展[J]. 植物营养与肥料学报, 27(6): 1080-1090. (Sun C, Liao D H, Wu S.2021. The advances of PHR and SPX in the nutrition signaling pathway[J]. Journal of Plant Nutrition and Fertilizers, 27(6): 1080-1090.) [2] 肖作义, 马飞, 柳开楼, 等. 2021. 红壤区旱地和水田土壤磷素状况及其流失风险[J]. 中国土壤与肥料, (01): 282-288. (Xiao Z Y, Ma F, Liu K L, et al. 2021. Current phosphorus status of red soil in drylands and paddy fields and its loss risks[J]. Soil and Fertilizer Sciences in China, (01): 282-288.) [3] 张苗, 周生财, 吴梦洁, 等. 2022. 闽楠中WRKY家族成员鉴定及缺磷胁迫下表达分析[J]. 林业科学, 58(02): 133-147. (Zhang M, Zhou S C, Wu M J, et al.2022. Identification of the PbWRKY gene family and its expression analysis under deficiency of phosphorus in Phoebe bournei[J]. Scientia Silvae Sinicae, 58(02): 133-147.) [4] Baek D, Chun H J, Yun D J, et al.2017. Cross-talk between phosphate starvation and other environmental stress signaling pathways in plants[J]. Molecules and Cells, 40(10): 697. [5] Baek D, Kim M C, Chun H J, et al.2013. Regulation of miR399f transcription by AtMYB2 affects phosphate starvation responses in Arabidopsis[J]. Plant Physiology, 161(1): 362-373. [6] Bustos R, Castrillo G, Linhares F, et al.2010. A central regulatory system largely controls transcriptional activation and repression responses to phosphate starvation in Arabidopsis[J]. PLOS Genetics, 6(9): e1001102. [7] Chen Y F, Li L Q, Xu Q, et al.2009. The WRKY6 transcription factor modulates PHOSPHATE1 expression in response to low Pi stress in Arabidopsis[J]. Plant Cell, 21(11): 3554-3566. [8] Chiou T J.2020. The diverse roles of rice PHO1 in phosphate transport: From root to node to grain[J]. Plant and Cell Physiology, 61(8): 1384-1386. [9] Decottignies A, Grant A M, Nichols J W, et al.1998. ATPase and multidrug transport activities of the overexpressed yeast ABC protein Yor1p[J]. Journal of Biological Chemistry, 273(20): 12612-12622. [10] Devaiah B N, Karthikeyan A S, Raghothama K G.2007. WRKY75 transcription factor is a modulator of phosphate acquisition and root development in Arabidopsis[J]. Plant Physiology, 143(4): 1789-1801. [11] Duan K, Yi K, Dang L, et al.2008. Characterization of a sub‐family of Arabidopsis genes with the SPX domain reveals their diverse functions in plant tolerance to phosphorus starvation[J]. The Plant Journal, 54(6): 965-975. [12] Hamburger D, Rezzonico E, Macdonald-Comber PetéTot J, et al.2002. Identification and characterization of the Arabidopsis PHO1 gene involved in phosphate loading to the xylem[J]. The Plant Cell, 14(4): 889-902. [13] Jung J Y, Ried M K, Hothorn M, et al.2018. Control of plant phosphate homeostasis by inositol pyrophosphates and the SPX domain[J]. Current Opinion in Biotechnology, 49: 156-162. [14] Kant S, Peng M, Rothstein S J.2011. Genetic regulation by NLA and microRNA827 for maintaining nitrate-dependent phosphate homeostasis in Arabidopsis[J]. PLOS Genetics, 7(3): e1002021. [15] Lin W Y, Lin S I, Chiou T J.2009. Molecular regulators of phosphate homeostasis in plants[J]. Journal of Experimental Botany, 60(5): 1427-1438. [16] Liu J, Fu S, Yang L, et al.2016. Vacuolar SPX-MFS transporters are essential for phosphate adaptation in plants[J]. Plant Signaling & Behavior, 11(8): e1213474. [17] Liu W, Sun Q, Wang K, et al.2017. Nitrogen limitation adaptation (NLA) is involved in source‐to‐sink remobilization of nitrate by mediating the degradation of NRT 1.7 in Arabidopsis[J]. New Phytologist, 214(2): 734-744. [18] Lv Q, Zhong Y, Wang Y, et al.2014. SPX4 negatively regulates phosphate signaling and homeostasis through its interaction with PHR2 in rice[J]. Plant Cell, 26(4): 1586-1597. [19] Park B S, Seo J S, Chua N H.2014. Nitrogen limitation adaptation recruits PHOSPHATE2 to target the phosphate transporter PT2 for degradation during the regulation of Arabidopsis phosphate homeostasis[J]. The Plant Cell, 26(1): 454-464. [20] Paz-Ares J, Puga M I, Rojas-Triana M, et al.2021. Plant adaptation to low phosphorus availability: Core signaling, crosstalks, and applied implications[J]. Molecular Plant, 15(1): 104-124. [21] Plaxton W C, Tran H T.2011. Metabolic adaptations of phosphate-starved plants[J]. Plant Physiology, 156(3): 1006-1015. [22] Puga M I, Mateos I, Charukesi R, et al.2014. SPX1 is a phosphate-dependent inhibitor of phosphate starvation response 1 in Arabidopsis[J]. Proceedings of the National Academy of Sciences of the USA, 111(41): 14947-14952. [23] Qi W, Manfield I W, Muench S P, et al.2017. AtSPX1 affects the AtPHR1-DNA-binding equilibrium by binding monomeric AtPHR1 in solution[J]. Biochemical Journal, 474(21): 3675-3687. [24] Quistgaard E M, Löw C, Guettou F, et al.2016. Understanding transport by the major facilitator superfamily (MFS): Structures pave the way[J]. Nature Reviews Molecular Cell Biology, 17(2): 123-132. [25] Secco D, Baumann A, Poirier Y.2010. Characterization of the rice PHO1 gene family reveals a key role for OsPHO1;2 in phosphate homeostasis and the evolution of a distinct clade in dicotyledons[J]. Plant Physiology, 152(3): 1693-1704. [26] Secco D, Wang C, Arpat B A, et al.2012. The emerging importance of the SPX domain‐containing proteins in phosphate homeostasis[J]. New Phytologist, 193(4): 842-851. [27] Secco D, Wang C, Shou H, et al.2012. Phosphate homeostasis in the yeast Saccharomyces cerevisiae, the key role of the SPX domain-containing proteins[J]. FEBS Letters, 586(4): 289-295. [28] Shi J, Hu H, Zhang K, et al.2014. The paralogous SPX3 and SPX5 genes redundantly modulate Pi homeostasis in rice[J]. Journal of Experimental Botany, 65(3): 859-870. [29] Srivastava S, Upadhyay M K, Srivastava A K, et al.2018. Cellular and subcellular phosphate transport machinery in plants[J]. International Journal of Molecular Sciences, 19(7): 1914. [30] Stefanovic A, Ribot C, Rouached H, et al.2007. Members of the PHO1 gene family show limited functional redundancy in phosphate transfer to the shoot, and are regulated by phosphate deficiency via distinct pathways[J]. The Plant Journal, 50(6): 982-994. [31] Su T, Xu Q, Zhang F C, et al.2015. WRKY42 modulates phosphate homeostasis through regulating phosphate translocation and acquisition in Arabidopsis[J]. Plant Physiology, 167(4): 1579-1591. [32] Wang C, Huang W, Ying Y, et al.2012. Functional characterization of the rice SPX-MFS family reveals a key role of OsSPX-MFS1 in controlling phosphate homeostasis in leaves[J]. New Phytologist, 196(1): 139-148. [33] Wang C, Ying S, Huang H, et al.2009. Involvement of OsSPX1 in phosphate homeostasis in rice[J]. The Plant Journal, 57(5): 895-904. [34] Wang C, Yue W, Ying Y, et al.2015. Rice SPX-Major Facility Superfamily3, a vacuolar phosphate efflux transporter, is involved in maintaining phosphate homeostasis in rice[J]. Plant Physiology, 169(4): 2822-2831. [35] Wang F, Deng M, Xu J, et al.2018. Molecular mechanisms of phosphate transport and signaling in higher plants[J]. Seminars in Cell & Developmental Biology, 74: 114-122. [36] Wang H, Xu Q, Kong Y H, et al.2014. Arabidopsis WRKY45 transcription factor activates PHOSPHATE TRANSPORTER1; 1 expression in response to phosphate starvation[J]. Plant Physiology, 164(4): 2020-2029. [37] Wang Z, Ruan W, Shi J, et al.2014. Rice SPX1 and SPX2 inhibit phosphate starvation responses through interacting with PHR2 in a phosphate-dependent manner[J]. Proceedings of the National Academy of Sciences of the USA, 111(41): 14953-14958. [38] Wild R, Gerasimaite R, Jung J Y, et al.2016. Control of eukaryotic phosphate homeostasis by inositol polyphosphate sensor domains[J]. Science, 352(6288): 986-990. [39] Yang J, Wang L, Mao C, et al.2017. Characterization of the rice NLA family reveals a key role for OsNLA1 in phosphate homeostasis[J]. Rice, 10(1): 52. [40] Yang W T, Baek D, Yun D J, et al.2018. Rice OsMYB5P improves plant phosphate acquisition by regulation of phosphate transporter[J]. PLOS One, 13(3): e0194628. [41] Zhang J, Zhu Y, Pan Y, et al.2018. Transcriptomic profiling and identification of candidate genes in two Phoebe bournei ecotypes with contrasting cold stress responses[J]. Trees, 32(5): 1315-1333. [42] Zhang Z, Liao H, Lucas W J.2014. Molecular mechanisms underlying phosphate sensing, signaling, and adaptation in plants[J]. Journal of Integrative Plant Biology, 56(3): 192-220. [43] Zhong Y, Wang Y, Guo J, et al.2018. Rice SPX6 negatively regulates the phosphate starvation response through suppression of the transcription factor PHR2[J]. New Phytologist, 219(1): 135-148. [44] Zhou J, Hu Q, Xiao X, et al.2021. Mechanism of phosphate sensing and signaling revealed by rice SPX1-PHR2 complex structure[J]. Nature Communications, 12(1): 1-10.
