• Effects of continuous cropping on fungal community structure succession in rhizosphere and non-rhizosphere soils of cassava

    Subjects: Biology >> Botany >> Applied botany submitted time 2024-05-15 Cooperative journals: 《广西植物》

    Abstract: For revealing the mechanism of cassava continuous cropping obstacle formation, the current study planted cassava in a fixed field for three consecutive years, and applied high-throughput sequencing technology and bioinformatics to explore effects of continuous cropping on fungal community structure of both rhizosphere and non-rhizosphere of cassava soils. The results were as follows: (1) Continuous cropping caused significant effects on the α diversity and β diversity of rhizosphere and non-rhizosphere soils of cassava. (2) The dominant fungi phyla of cassava rhizosphere and non-rhizosphere soils were Ascomycota, SAR_k__norank, Basidiomycota, Mucoromycota, and unclassified _k __Fungi, while the main classes were Sordariomycetes, Eurotiomycetes, Dothideomycetes and Intramacronucleata. The composition of Ascomycota of the non-rhizosphere soils varied with the continuous cropping years significantly. In the rhizosphere, Hypocreales, Chaetothyriales, Myrothecium, Dothideomycetes, and Sordariomycetes were observed in 2019 and 2020, while Monosiga was found in 2021. (3) Soil pH, organic matter content, available nitrogen content, available phosphorus content, available potassium content, and urease activity significantly influenced the structure of fungal communities, especially for distributions of Ascomycota, SAR_k__norank, Basidiomycota, and Mucoromycota. In conclusion, continuous cropping of cassava influenced soil physicochemical properties through the accumulation of root exudates, thus altering the survival environment of fungi, leading to differences of the diversity and the abundance of fungal communities between cassava rhizosphere and non-rhizosphere soils. The relative abundance of Hypocreales, Myrothecium, and Sordariomycetes decreased with continuous cropping years, which may be one of main causes of the continuous cropping obstacles of cassava.

  • Effects of climatic factors on the fruit quality of Siraitia grosvenorii and its molecular regulation mechanism

    Subjects: Biology >> Botany >> Applied botany submitted time 2024-02-07 Cooperative journals: 《广西植物》

    Abstract: In order to investigate the impact of climatic factors on the quality of Siraitia grosvenorii fruits pollinated in different seasons and the underlying molecular mechanism involved, the differences in climate factors, quality traits, and gene expression between fruits of the main cultivar S. grosvenorii “Qingpiguo” pollinated in summer and autumn were statistically analyzed by monitoring climate factors at different developmental stages, measuring morphological changes, detecting mogroside metabolism, and analyzing gene expression using qRT-PCR. The results were as follows: (1) compared to summer-pollinated fruits, the average temperature and effective accumulated temperature of autumn-pollinated fruits decreased significantly after 35 d. Additionally, the temperature difference between day and night increased significantly before 65 d. However, this difference was still less than that of the average temperature and effective accumulated temperature. The light intensity and air humidity remained similar. (2) The transverse diameters, longitudinal diameters, and single fruit weights of autumn-pollinated fruits increased compared to those of summer-pollinated fruits, however, these differences were not statistically significant. (3) Mogroside V and 11-O-mogroside V in autumn-pollinated fruits accumulated slowly from 55 d with a delay of about 10 days, moreover, the content of both compounds in ripe fruits decreased by 40.66 % and 46.07 %, respectively. (4) The number and extent of up-regulated mogroside V genes were relatively lower, and their co-expression consistency was poorer. Furthermore, the glucosyltransferase gene SgUGT94-289-3, responsible for the final step in mogroside V biosynthesis, exhibited down-regulation at all time points of 55 d. In summary, the shape and size of S. grosvenorii fruits pollinated in different seasons were not significantly affected by climatic factors; however, the content of mogroside V was significantly influenced by the temperature, which potentially influences these variations in mogroside V by regulating both the co-expression consistency and expression level of mogroside V genes. The results of this study can provide theoretical basis for high-quality cultivation and genetic breeding of S. grosvenorii.

  • 檀香NDH 脱氢酶基因的克隆、定位与启动子分析

    Subjects: Biology >> Botany >> Applied botany submitted time 2023-10-22 Cooperative journals: 《广西植物》

    Abstract:为研究檀香NDH 脱氢酶基因的功能和调控机制,以檀香心材为材料,利用RACE 技术克隆SaNDH6 基因的全长序列,利用实时荧光定量PCR(RT-qPCR)技术分析其组织 和激素处理后的表达模式,在拟南芥原生质体观测其亚细胞定位,利用PlantCARE 分析 SaNDH6 起始密码子ATG 上游2 kb 的启动子序列,同时运用PlantRegMap 预测可能与其结 合的转录因子。结果表明:(1)SaNDH6 编码303 个氨基酸,为疏水蛋白,亚细胞定位于 叶绿体。(2)进化树分析表明,檀香SaNDH6 与木本植物NDH6 进化关系较近。(3)PlantCARE 分析发现,SaNDH6 启动子中除含有ACE、AE-box、Box 4、G-Box 和GT1-motif 等大量光 响应元件外,同时还有茉莉酸甲酯(MeJA)反应元件CGTCA-motif 和TGACG-motif,赤霉 素(GA)响应元件P-box,以及防御和胁迫响应元件TC-rich repeats 等。(4)通过PlantRegMap 分析发现,有76 个转录因子可能与SaNDH6 启动子结合,其中ERF 家族最多,达到了40 个。(5)SaNDH6 在檀香的根、心材、叶片和愈伤组织中均有表达,其中在叶片中的表达 量较高;用110-4 molL-1 的MeJA 和GA3 分别处理檀香愈伤组织后,SaNDH6 的表达均显 著升高。综上结果表明,檀香SaNDH6 为核基因编码的蛋白,受光和激素等诱导表达,可 能参与檀香逆境胁迫反应的过程。

  • 甘蔗幼苗对难溶性磷的吸收及其根系对低磷胁迫的响应

    Subjects: Biology >> Botany >> Applied botany submitted time 2018-12-19 Cooperative journals: 《广西植物》

    Abstract:南方酸性土壤中的全磷含量高,但有效磷普遍偏低,土壤磷素不足是制约甘蔗生长的重要因素。明确甘蔗适应低磷胁迫的生理生化机制,挖掘甘蔗对磷素的利用潜力,对指导甘蔗育种及栽培管理均有重要的理论与现实意义。本文以ROC22和ROC 10两个甘蔗品种为材料,采用水培和土培的试验方法研究了甘蔗幼苗对难溶性磷的吸收及其在低磷胁迫下根构型和根系的生理反应,以揭示甘蔗对低磷胁迫适应的可能机制。结果表明:C1)培养在以难溶性磷CCa-P和A1-P}为磷源的培养液中的甘蔗的叶片数、地上部干重、生物量较缺磷 (-P)处理显著增加,与对照(+P)的相当,甘蔗总磷积累量也显著提高,达到对照(+P)处理磷积累量的30%^-77%o C2)在低磷条件下,甘蔗幼苗的根系有向土壤深层分布的趋势,根的总体积增大,最长根长变长,浅根系分布增多。C3)甘蔗幼苗在低磷环境下,根际环境明显酸化,且根系分泌物能溶解难溶性的铝磷,植株体内酸性磷酸酶的活性也明显增强。上述结果表明,甘蔗幼苗有较强的吸收利用难溶性磷的能力,而低磷条件下根系数量增加,主根的向地性,浅根系分布增多,根际酸化以及植株体内酸性磷酸酶活性的增强可能是甘蔗幼苗适应缺磷环境的重要机制。