Abstract
Rhizopus oryzae causes tobacco pole rot in China during tobacco flue-curing. Flue-curing is a post-harvest process done to prepare tobacco leaves and involves three different stages: the yellowing stage has the lowest temperatures and highest humidity, then the color-fixing stage has higher temperatures and medium humidity, and finally the stem-drying stage has the highest temperatures and lowest humidity. In this study, fungal culturing and IonS5XL high-throughput sequencing techniques were used to reveal the fungal community of the petioles and lamina of tobacco leaves infected with pole rot during flue-curing. A total of 108 fungal isolates belonging to 6 genera were isolated on media. The most common fungal species isolated was the pathogen, R. oryzae, that was most often found equally on petioles and laminas in the color-fixing stage, followed by saprotrophs, mostly Aspergillus spp. High-throughput sequencing revealed saprotrophs with Alternaria being the most abundant genus, followed by Phoma, Cercospora, and Aspergillus, whereas Rhizopus was the tenth most abundant genus, which was mostly found on petioles at the yellowing stage. Both culturable fungal diversity and fungal sequence diversity was higher at stem-drying stage than the yellowing and color-fixing stages, and diversity was higher with leaf lamina than petioles revealing that the changes in fungal composition and diversity during the curing process were similar with both methods. This study demonstrates that the curing process affects the leaf microbiome of tobacco during the curing process, and future work could examine if any of these saprotrophic fungi detected during the curing of tobacco leaves may be potential biocontrol agents for with pole rot in curing chambers.
Highlights
Tobacco (Nicotiana tabacum L.) is a leafy, annual, solanaceous plant grown commercially for its leaves
The results reveal changes in the fungi associated with leaves having pole rot in a curing chamber, providing a list of saprobes present naturally present during the curing process that could be examined in the future as antagonists for biocontrol of tobacco pole rot
During the curing process where tobacco pole rot occurs in the curing chamber, relative humidity declined from 84−91.5% to 8.5−22%, lamina wetness declined from 63−67% to 4−14%, and petiole wetness declined from 73−78% to 5−20% (Table 1)
Summary
Tobacco (Nicotiana tabacum L.) is a leafy, annual, solanaceous plant grown commercially for its leaves. It is one of the most widely grown commercial non-food crop in the world (Liu et al, 2017). The leaves of tobacco are normally first harvested in commercial field and flue-cured in a baking barn (Naidu, 2001). The purpose of flue-curing is to produce dried leaves of suitable physical. Many pathogens can attack the plant causing lesions and rots of tobacco leaves, including bacteria such as Erwinia carotovora and Bacillus polymyxa (Spurr, 1980), and fungi such as Aspergillus, Penicillium, Alternaria, and Cladosporium (Welty et al, 1968)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
