Institute of Fruit and Floriculture Research, Gansu Academy of Agricultural Sciences, Lanzhou, Gansu Province, People's Republic of China.
PLoS One. 2020 Oct 12;15(10):e0239737. doi: 10.1371/journal.pone.0239737. eCollection 2020.
Different densities have a great influence on the physiological process and growth of orchard plants. Exploring the molecular basis and revealing key candidate genes for different densities management of orchard has great significance for production capacity improvement. In this study, transcriptome sequencing of apple trees was carried out at three different sampling heights to determine gene expression patterns under high density(HD) and low density(LD) and the physiological indices were measured to determine the effect of density change on plants. As a result, physiological indexes showed that the content of Chlorophyll, ACC, RUBP and PEP in the LD was apparently higher than that in control group(high density, HD). While the content of PPO and AO in the LD was noticeably lower than that in the HD. There were 3808 differentially expressed genes (DEGs) were detected between HD and LD, of which 1935, 2390 and 1108 DEGs were found in the three comparisons(middle-upper, lower-outer and lower-inner), respectively. 274 common differentially expressed genes (co-DEGs) were contained in all three comparisons. Functional enrichment and KEGG pathway analysis found these genes were involved in Carbon fixation in photosynthetic organisms, Circadian rhythm, Photosynthesis - antenna proteins, Photosynthesis, chlorophyll metabolism, Porphyrin, sugar metabolism and so on. Among these genes, LHCB family participated in photosynthesis as parts of photosystem II. In addition, SPA1, rbcL, SNRK2, MYC2, BSK, SAUR and PP2C are involved in Circadian rhythm, the expression of genes related to glycometabolism and hormone signaling pathway is also changed. The results revealed that the decrease of plant density changed the photosynthetic efficiency of leaves and the expression of photosynthesis-related genes, which provide a theoretical basis for the actual production regulation of apples.
不同的密度对果园植物的生理过程和生长有很大的影响。探索不同密度管理的分子基础和揭示关键候选基因对提高苹果产量具有重要意义。本研究通过对三种不同采样高度的苹果树进行转录组测序，确定了高密度(HD)和低密度(LD)下的基因表达模式，并测量了生理指标，以确定密度变化对植物的影响。结果表明，生理指标显示，LD 中叶绿素、ACC、RUBP 和 PEP 的含量明显高于对照组(高密度，HD)。而 LD 中 PPO 和 AO 的含量明显低于 HD。在 HD 和 LD 之间检测到 3808 个差异表达基因(DEGs)，其中在三个比较(middle-upper、lower-outer 和 lower-inner)中分别发现了 1935、2390 和 1108 个 DEGs。在所有三个比较中都包含 274 个共同差异表达基因(co-DEGs)。功能富集和 KEGG 通路分析发现这些基因参与光合生物的碳固定、昼夜节律、光合作用天线蛋白、光合作用、叶绿素代谢、卟啉、糖代谢等。在这些基因中，LHCB 家族作为光系统 II 的一部分参与光合作用。此外，SPA1、rbcL、SNRK2、MYC2、BSK、SAUR 和 PP2C 参与昼夜节律，糖代谢和激素信号通路相关基因的表达也发生了变化。结果表明，植物密度的降低改变了叶片的光合作用效率和光合作用相关基因的表达，为苹果的实际生产调控提供了理论依据。
