de la Torre-Hernández María Eugenia, Salinas-Virgen Leilani I, Aguirre-Garrido J Félix, Fernández-González Antonio J, Martínez-Abarca Francisco, Montiel-Lugo Daniel, Ramírez-Saad Hugo C
CONACYT-Universidad Autónoma Metropolitana-Xochimilco, Mexico City, Mexico.
Maestría en Ciencias Agropecuarias, Universidad Autónoma Metropolitana-Xochimilco, Mexico City, Mexico.
Front Microbiol. 2020 Jun 26;11:1424. doi: 10.3389/fmicb.2020.01424. eCollection 2020.
The Queretaro semi-desert in central Mexico is the most southern extension of the Chihuahua desert. This semi-arid zone shelters a vast cactus diversity with many endemic species. Currently, two cacti species from this semi-desert namely, and are under a threat to their survival. So far, there are no reports on the bacterial communities associated with these plants. In this study, we assessed the structure and diversity of the rhizospheric bacterial communities associated with and growing in wild and cultivated conditions. Samples of were also approached with culture-based methods in search of isolates with plant growth promoting abilities. Metagenomic DNA was extracted from rhizospheric samples and used for Illumina sequencing of the 16S rRNA gene. α-diversity and amplicon sequence variant (ASV) richness were higher in both groups of samples. All samples accounted for 14 phyla, and the major 6 were common to all treatments. The dominant phyla in all four sample groups were and . Analysis at family and genus levels showed association patterns with the cultivated samples from both species grouping together, while the wild samples of each cactus species were grouping apart. High abundance values of Rubrobacteraceae (15.9-18.4%) were a characteristic feature of wild samples. In total, 2,227 ASVs were scored in all 12 rhizospheric samples where samples showed higher richness with 1,536 ASVs. Regarding the growing conditions, both groups of cultivated samples were also richer accounting for 743 and 615 ASVs for and , respectively. The isolates from rhizosphere were mainly assigned to and . In total 35 strains were assayed for PGPR traits (IAA and siderophore production, phosphate solubilization, and fungal growth inhibition). Strains obtained from plants growing in the wild displayed better PGPR characteristics, stressing that naturally occurring wild plants are a source of bacteria with diverse metabolic activities, which can be very important players in the adaptation of cacti to their natural environments.
墨西哥中部的克雷塔罗半沙漠是奇瓦瓦沙漠最南端的延伸地带。这个半干旱地区拥有丰富的仙人掌种类,其中许多是特有物种。目前,来自这片半沙漠的两种仙人掌,即[具体仙人掌种类1]和[具体仙人掌种类2],正面临生存威胁。到目前为止,尚无关于与这些植物相关的细菌群落的报道。在本研究中,我们评估了在野生和栽培条件下生长的[具体仙人掌种类1]和[具体仙人掌种类2]根际细菌群落的结构和多样性。还采用基于培养的方法对[具体仙人掌种类1]的样本进行分析,以寻找具有促进植物生长能力的分离株。从根际样本中提取宏基因组DNA,并用于16S rRNA基因的Illumina测序。两组[具体仙人掌种类1]样本的α多样性和扩增子序列变体(ASV)丰富度均较高。所有样本共涉及14个门,其中主要的6个门在所有处理中都有。所有四个样本组中的优势门是[优势门1]和[优势门2]。在科和属水平上的分析表明,两种仙人掌的栽培样本呈现出关联模式并聚在一起,而每种仙人掌的野生样本则分开聚类。红杆菌科(15.9 - 18.4%)的高丰度值是野生[具体仙人掌种类1]样本的一个特征。在所有12个根际样本中共记录了2227个ASV,其中[具体仙人掌种类1]样本的丰富度更高,有1536个ASV。关于生长条件,两组栽培样本也更丰富,[具体仙人掌种类1]和[具体仙人掌种类2]的栽培样本分别有743个和615个ASV。从[具体仙人掌种类1]根际分离出的菌株主要属于[属1]和[属2]。总共对35株菌株进行了植物生长促进根际细菌(PGPR)特性检测(吲哚 - 3 - 乙酸和铁载体产生、磷溶解以及真菌生长抑制)。从野生环境中生长的植物获得的菌株表现出更好的PGPR特性,强调自然生长的野生植物是具有多种代谢活动的细菌的来源,这些细菌在仙人掌适应其自然环境中可能是非常重要的参与者。