Global Plant Protection News

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Thursday, 17 February 2022 06:49:28

Grahame Jackson posted a new submission ‘ PANTOEA LEAF BLIGHT, RICE – CHINA: FIRST REPORT’

Submission

PANTOEA LEAF BLIGHT, RICE – CHINA: FIRST REPORT

ProMED
http://www.promedmail.org

Source: Plant Disease [summ. Mod.DHA, edited]
https://doi.org/10.1094/PDIS-05-21-0988-PDN

Citation: Yu L, Yang C, Ji Z, et al. First Report of New Bacterial Leaf Blight of Rice Caused by _Pantoea ananatis_ in Southeast China. Plant Disease. 2022; 106 (1); doi: 10.1094/PDIS-05-21-0988-PDN.
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In autumn 2020, leaf blight was observed on a number of varieties of rice (_Oryza sativa_) in Zhejiang and Jiangxi provinces. The disease incidence was 45-60%. The symptoms were assumed to be caused by _Xanthomonas oryzae_ pv. _oryzae_ (Xoo), the pathogen of rice bacterial blight.

Sixty-three isolates were obtained from collected diseased leaves. 16S rRNA sequence analysis from 6 isolates revealed that the amplified fragments shared 98% similarity with the _Pantoea ananatis_ type strain in GenBank. Analysis of further sequences and phylogenetic analyses was carried out. Based on the obtained morphological, physiological, biochemical, and molecular data, the isolates were confirmed as _P. ananatis_. Pathogenicity tests resulted in symptoms similar to those in the field.

_P. ananatis_ has previously been reported to cause grain discolouration of rice in the country, but this is the 1st report of _P. ananatis_ as the causative agent of rice leaf blight. This raises the alarm that the emerging rice bacterial leaf blight might be caused by _P. ananatis_, instead of Xoo as traditionally assumed. Further, the differences of occurrence, spread, and control between these 2 diseases will need to be determined.

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Communicated by:
ProMED

[_Pantoea ananatis_ symptoms in rice may include lesions on stems, stem necrosis, and leaf blight. The pathogen has also been reported to cause sheath and grain rot, as well as kernel discolouration. _P. stewartii_, previously known to occur on rice seeds, has also recently been associated with a leaf blight of the crop in Africa (ProMED post 20170504.5012251). Both species are considered emerging rice pathogens. The effects of different bacterial strains on hosts can vary dramatically. The bacteria are generally transmitted by insect vectors, plant material, and infected seed, making them a quarantine risk.

Species in the genus can cause diseases on a number of crops, such as Stewart’s bacterial wilt on maize and fruit bronzing of jack fruit (_P. stewartii_); leaf blights of cereals, including rice (_P. agglomerans_); pink disease of pineapple (_P. citrea_); brown stalk rot of maize (_P. ananatis_ and a novel _Pantoea_ species); and centre rot of onion (_P. ananatis_). A bacterial blight of _Eucalyptus_ and a leaf blotch disease of sudangrass have also been associated with _Pantoea_ species.

_Xanthomonas oryzae_ pv. _oryzae_ (Xoo) causes bacterial leaf blight (BLB) of rice. In Asia, millions of hectares of rice paddies are severely affected every year, with reported yield losses of up to 60% (e.g., see ProMED post 20211216.8700304). Xo pv. _oryzicola_ (Xoc) is the causal agent of bacterial leaf streak (BLS; e.g., see ProMED post 20210713.8514345), which is currently considered one of the most important emerging diseases of rice in the region. Xoc is thought to have originated in Asia but is now also spreading in Africa (e.g., recent 1st report from Senegal, see link below).

Maps
China:
http://www.beijing-travels.com/image/chinamap.jpg
China provinces:
http://www.chinadiscovery.com/assets/images/customer-support/maps/china-provinces-map-600.jpg

Pictures
_P. ananatis_ symptoms on rice:
http://www.publish.csiro.au/temp/AP04053_F1.gif

Links
_P. ananatis_ on rice:
http://dx.doi.org/10.1094/PDIS-06-11-0533
https://doi.org/10.1094/PDIS-94-4-0482B and
http://dx.doi.org/10.5197/j.2044-0588.2015.032.021
Information & review on _P. ananatis_:
https://doi.org/10.1111/j.1364-3703.2009.00542.x and
https://www.researchgate.net/figure/Host-range-of-Pantoea-ananatis_tbl1_24375785
_P. ananatis_ taxonomy and strains:
https://www.uniprot.org/taxonomy/553 and
https://doi.org/10.1128/JB.06450-11
Description of genus _Pantoea_:
http://www.tgw1916.net/Enterobacteria/Pantoea.html
Information on _Pantoea_ species and subspecies:
http://www.bacterio.net/pantoea.html and
https://doi.org/10.1128/JCM.01916-08
First report of Xoc in Senegal 2022:
https://doi.org/10.1094/PDIS-11-21-2481-PDN
Genus _Xanthomonas_ taxonomy, species & strains via:
https://www.uniprot.org/taxonomy/338
– Mod.DHA]