Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), Institute of Agro-Bioengineering/College of Life Sciences, Guizhou University, Guiyang 550025, China.
Institute of Pomology Science, Guizhou Academy of Agricultural Sciences, Guiyang 550006, China.
Int J Mol Sci. 2022 Apr 28;23(9):4896. doi: 10.3390/ijms23094896.
Phosphorus (Pi) is a macronutrient essential for plant growth, development, and reproduction. However, there is not an efficient available amount of Pi that can be absorbed by plants in the soil. Previously, an elite line, MSDZ 109, selected from , was justified for its excellent tolerance to low phosphorus (low-Pi) stress. To date, however, the genes involved in low-Pi stress tolerance have not yet been unraveled in this species. Currently, the physiological responses of this line for different days to low-Pi stress were characterized, and their roots as well as leaves were used to carry out transcriptome analysis, so as to illuminate the potential molecular pathways and identify the genes involved in low-Pi stress-response. After exposure to low-Pi treatment (32 µmol/L KHPO) for 20 day after treatment (DAF) the biomass of shoots was significantly reduced in comparison with that of the stress-free (control), and root architecture diversely changed. For example, the root growth parameters e.g., length, surface area, and total volume somewhat increase in comparison with those of the control. The activity of acid phosphatase (ACP) increased with the low-Pi treatment, whereas the photosynthetic rate and biomass were declining. The activity of antioxidant enzymes, e.g., superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), were substantially elevated in response to low-Pi treatment. Many enzyme-related candidate genes e.g., , and were up-regulated to low-Pi treatment. Furthermore, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that the processes of photosynthesis, plant hormone signal transduction, and MAPK signaling pathway were affected in the low-Pi response. In combination with the physiological characterization, several low-Pi-responsive genes, e.g., PHT, PHO, were identified, and the genes implicated in Pi uptake and transport, such as , , , etc., were also obtained since their expression status varied among the exposure times, which probably notifies the candidates involved in low-Pi-responsive tolerance in this line. Interestingly, low-Pi treatment activated the expression of transcription factors including the WRKY family, MYB family, etc. The available evidences will facilitate a better understanding of the roles of this line underlying the high tolerance to low-Pi stress. Additionally, the accessible data are helpful for the use of the apple rootstock under low-Pi stress.
磷（Pi）是植物生长、发育和繁殖所必需的大量营养素。然而，土壤中可被植物吸收的有效磷（Pi）含量并不高。此前，从 中筛选出的优良品系 MSDZ 109 因其对低磷（Pi）胁迫的优异耐受性而得到证明。然而，到目前为止，该物种中涉及低 Pi 胁迫耐受性的基因尚未被揭示。目前，对该品系在不同低 Pi 胁迫天数下的生理反应进行了表征，并对其根和叶进行了转录组分析，以阐明潜在的分子途径，并鉴定与低 Pi 胁迫反应相关的基因。在低 Pi 处理（32 µmol/L KHPO）20 天后，与无胁迫（对照）相比，地上部生物量显著减少，根系结构也发生了不同程度的变化。例如，与对照相比，根生长参数（如长度、表面积和总体积）略有增加。酸性磷酸酶（ACP）的活性随着低 Pi 处理的增加而增加，而光合速率和生物量则下降。抗氧化酶（如超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT））的活性在低 Pi 处理下显著升高。许多与酶相关的候选基因（如 、 和 ）在低 Pi 处理下上调。此外，京都基因与基因组百科全书（KEGG）途径分析表明，光合作用、植物激素信号转导和 MAPK 信号通路的过程受到低 Pi 反应的影响。结合生理特征，鉴定了几个低 Pi 响应基因，如 PHT、PHO 等，以及 Pi 吸收和转运相关基因，如 、 、 等，因为它们的表达状态在不同的暴露时间之间有所不同，这可能提示了该品系中低 Pi 响应耐受力涉及的候选基因。有趣的是，低 Pi 处理激活了转录因子（如 WRKY 家族、MYB 家族等）的表达。这些证据将有助于更好地理解该品系在高耐低 Pi 胁迫方面的作用。此外，这些可利用的数据有助于在低 Pi 胁迫下使用苹果砧木 。
