Amaranthus caudatus subsp. mantegazzianus: A new host of ‘Candidatus Phytoplasma hispanicum’ (subgroup 16Sr XIII‐A)

Abstract

In Argentina, amaranth is a promising crop due to high nutritional quality and ability to grow in a diversity of environments. In areas cultivated with amaranth, were observed plants exhibiting slow growth, deformed leaves, proliferation of shoots and malformed lateral panicles. Field survey revealed up to 96% disease incidence and 92% of the seeds collected from mother plants produced diseased seedlings. A phytoplasma was detected in association with seedlings and adult plants using nested PCR assays. Molecular identification by computer‐simulated RFLP and phylogenetic analysis evidenced the occurrence of a ‘Candidatus Phytoplasma hispanicum’‐related strain, affiliated with 16SrXIII‐A subgroup. The findings implicate amaranth as a new host for this subgroup and as a potential reservoir of the pathogen for other cultivated species. In addition, to the best of our knowledge, this study reports for the first time the presence of 16SrXIII‐A phytoplasma in Argentina and in South America. Furthermore, transmission assays pointed that naturally infected seed is an important vehicle of dissemination of the pathogen, threatening the expansion of the crop for new geographical areas.

Lactobacillus plantarum and propionic acid improve the fermentation quality of high-moisture amaranth silage by altering the microbial community composition

“…Xanthomonas differs from non-pathogenic bacteria in that it relies on a variety of potent substances secreted through different kinds of protein secretion systems, predominantly the type III secretion system, to suppress host immunity and to obtain nutrients from plants. Amaranth was considered a promising crop in Argentina ( Noelting et al, 2019 ), but was found to be a host of Xanthomonas euvesicatoria ( Santos et al, 2020 ), Curtobacterium flaccumfaciens pv. flaccumfaciens ( Nascimento et al, 2020 ), and Xanthomonas citri subsp.…”

First report of a ‘Candidatus Phytoplasma australasia’ related strain (16SrII‐D) associated with Amaranthus hypochondriacus inflorescence malformation in India

“…mantegazzianus and A. retroflexus , were reported as hosts of ‘ Ca . P. hispanicum’ (subgroup 16Sr XIII‐A) from Argentina (Noelting et al. , 2019) and ‘ Ca .…”

“…mantegazzianus and A. retroflexus, were reported as hosts of 'Ca. P. hispanicum' (subgroup 16Sr XIII-A) from Argentina (Noelting et al, 2019) and 'Ca. Phytoplasma ziziphi' (subgroup 16SrV-B) in China (Long et al, 2011), respectively.…”