CIRAD, UMR AGAP, Montpellier, France.
AGAP, Université de Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France.
PLoS One. 2019 Jun 20;14(6):e0218528. doi: 10.1371/journal.pone.0218528. eCollection 2019.
While potassium fertilization increases growth yield in Brazilian eucalyptus plantations, it could also increase water requirements, making trees more vulnerable to drought. Sodium fertilization, which has been shown to promote eucalyptus growth compared to K-deficient trees, could partially mitigate this adverse effect of potassium. However, little is known about the influence of K and Na fertilization on the tree metabolic response to water deficit. The aim of the present study was thus to analyze the transcriptome of leaves sampled from Eucalyptus grandis trees subjected to 37% rainfall reduction, and fertilized with potassium (K), sodium (Na), compared to control trees (C). The multifactorial experiment was set up in a field with a throughfall exclusion system. Transcriptomic analysis was performed on leaves from two-year-old trees, and data analyzed using multifactorial statistical analysis and weighted gene co-expression network analysis (WGCNA). Significant sets of genes were seen to respond to rainfall reduction, in interaction with K or Na fertilization, or to fertilization only (regardless of the water supply regime). The genes were involved in stress signaling, primary and secondary metabolism, secondary cell wall formation and photosynthetic activity. Our focus on key genes related to cation transporters and aquaporins highlighted specific regulation of ion homeostasis, and plant adjustment to water deficit. While water availability significantly affects the transcriptomic response of eucalyptus species, this study points out that the transcriptomic response is highly dependent on the fertilization regime. Our study is based on the first large-scale field trial in a tropical region, specifically designed to study the interaction between water availability and nutrition in eucalyptus. To our knowledge, this is the first global transcriptomic analysis to compare the influence of K and Na fertilization on tree adaptive traits in water deficit conditions.
虽然钾施肥会增加巴西桉树种植园的生长产量，但它也会增加需水量，使树木更容易受到干旱的影响。与缺钾树木相比，钠施肥已被证明可以促进桉树生长，因此可以部分减轻钾的这种不利影响。然而，人们对钾和钠施肥对树木代谢对水分亏缺的反应的影响知之甚少。因此，本研究的目的是分析在降雨量减少 37%的情况下，用钾 (K)、钠 (Na) 施肥的巨桉叶片的转录组，与对照树 (C) 进行比较。该多因子实验是在一个具有穿透雨排除系统的田间进行的。对两年生树木的叶片进行转录组分析，并使用多因子统计分析和加权基因共表达网络分析 (WGCNA) 进行数据分析。研究发现，与钾或钠施肥相互作用或仅施肥（无论供水制度如何），有显著的基因集对降雨量减少做出响应。这些基因涉及应激信号、初级和次级代谢、次生细胞壁形成和光合作用活性。我们关注与阳离子转运体和水孔蛋白相关的关键基因，突出了离子稳态和植物对水分亏缺的调节的特定调节。虽然水分供应显著影响桉树物种的转录组反应，但本研究指出，转录组反应高度依赖于施肥制度。本研究基于在热带地区进行的首次大规模田间试验，专门研究了桉树中水分可用性和营养之间的相互作用。据我们所知，这是首次在水分亏缺条件下比较钾和钠施肥对树木适应性特征影响的全球转录组分析。
