Specialized bacteriome uncovered in the coralloid roots of the epiphytic gymnosperm, Zamia pseudoparasitica

Abstract

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Full-Length 16S rRNA and ITS Gene Sequencing Revealed Rich Microbial Flora in Roots of Cycas spp. in China

“…This finding is consistent with previous reports done on cycads microbiome. 8,14,15 Although in lesser abundance, the uncharacterized candidate phylum WPS-2 was also identified in some of the coralloid root samples and normal root of C. fairylakea but not in any C. debaoensis normal root samples. Dry, bare soil environment and close association with boreal moss was the common niche of this phylum 48 but rarely reported as associates of plant roots.…”

“…Its first occurrence in cycad was seen in coralloid root of epiphytic Zamia pseudoparasitica . 15 Therefore, this warrants the verification if these taxa were selected by cycads to be part of their root microbiome or simply a scavenger of their exudates. The non-photosynthetic genera comprising of the nitrogen-fixing soil bacteria Bradyrhizobium, Burkholderia, Rhizobium , and Mesorhizobium were also present in the roots of Cycas debaoensis and Cycas fairylakea and reportedly prevalent also in root-endosphere of Dioon spp.…”

“…Rhizobiales (Proteobacteria) in addition to the dominating Nostocales (Cyanobacteria), were found in the coralloid roots of cycad species, that is, Mexican Dioon spp., 13,14 Ceratozamia mexicana , South African Encephalartos villosus , 7 and epiphytic Panamian Zamia pseudoparasitica . 15 Although receiving very little attention, eukaryotic microbes such as fungi were also detected in cycad roots. The first evidence of fungal colonization came from visual observation of Fisher and Vovides 16 in the normal roots of some Zamiaceae species.…”

An in silico Study of Two Transcription Factors Controlling Diazotrophic Fates of the Azolla Major Cyanobiont Trichormus azollae

“…Interestingly, the genus Sphaerospermopsis (specifically Sphaerospermopsis aphanizomenoides BCCUSP55) has been shown to form a single two-member monophyletic clade with Trichormus azollae , with 64% bootstrap support between nodal tips, when the rbcL-rbcX molecular marker was employed. 21 Still, when whole genome phylogeny was inferred for cyanobacteria, the Trichormus azollae genome formed a monophyletic clade only with the genome of Sphaerospermopsis aphanizomenoides BCCUSP55 (Warshan et al, 2018). The genus Sphaerospermopsis forms coiled and straight filaments and, in some cases, has been originally thought as Anabaena , exclusively from morphology, and later changed in nomenclature based on molecular data gathering exercises.…”

The diversity and community structure of symbiotic cyanobacteria in hornworts inferred from long‐read amplicon sequencing

“…Until recently, research on the diversity of plant cyanobionts relied on culturing the cyanobacteria or limited methods of genetic differentiation such as RFLPs (Leizerovich et al, 1990;West and Adams, 1997;Costa et al, 1999Costa et al, , 2001Nilsson et al, 2000;Guevara et al, 2002;Zheng et al, 2002;Papaefthimiou et al, 2008;Rikkinen and Virtanen, 2008;Thajuddin et al, 2010;Yamada et al, 2012;Fernández-Martínez et al, 2013;Liaimer et al, 2016). While metabarcoding and metagenomic methods using nextgeneration-sequencing platforms have begun to be applied, covering Azolla, cycads, and one hornwort (Dijkhuizen et al, 2018;Zheng et al, 2018;Gutiérrez-García et al, 2019;Suárez-Moo et al, 2019;Zheng and Gong, 2019;Bell-Doyon et al, 2020;Bouchard et al, 2020), we are still far from fully capturing the diversity of plant cyanobionts and any patterns of host preferences. The conventional 16 S amplicon approach for barcoding bacteria poses several challenges in characterizing cyanobiont communities.…”