ABSTRACT
Leaf mustard (Brassica juncea [L.] Czern. et Coss.) belongs to Brassicaceae and is an important leaf vegetable widely cultivated in the Yangtze River basin and various southern provinces in China. In August 2023, the rhizome decay symptoms were observed at the stem base of leaf mustard plants (cv. Huarong) in the field of Changde City (29.05 °N; 111.59 °E), Hunan Province, China. The incidence of symptomatic leaf mustard was approximately 30% in several fields (2 ha in total). Brown and water-soaked symptoms appeared at the base of the outer leaves, and hollow rot at the base of the stem, accompanied by a fishy odor. To identify the causal agent, six infected stem samples were collected and surface sterilized by soaking in 75% ethanol for 60 seconds, rinsed three times with sterile distilled water, and finally cut into pieces (5 × 5 mm) in the sterile water. The extract was streaked on nutrient agar medium. After incubation at 28°C for 24 h, 17 strains were obtained and the colonies of all strains were creamy white, roughly circular, and convex elevation. Six single bacterial strains JC23121001-JC23121006, individually isolated from six different diseased stem samples, were selected as representative strains for further study. For preliminary identification, DNA from the six strains was extracted and identified by 16S rDNA sequencing using the universal primer pair 27F/1492R (Weisburg et al. 1991), and the sequences (accession nos. PP784484 to PP784489) showed 99% query coverage and 99.65% identity to Pectobacterium brasiliense type strain IBSBF1692T (Nabhan et al. 2012). In addition, five housekeeping genes acnA, mdh, mltD, pgi, and proA of the six strains were amplified with specially designed primers (Ma et al. 2007), and the resulting sequences from all six strains were 100% identical. The sequences of the representative strain JC23121001 were deposited into GenBank with accession numbers PP108247, PP066857, PP108248, PP066858, and PP066860, respectively. The maximum-likelihood phylogenetic tree clustered JC23121001 with P. brasiliense type strain IBSBF1692T (Nabhan et al. 2012). The pathogenicity test of six strains was carried out on the six-week-old leaf mustard (cv. Huarong) plants grown in the greenhouse by inoculating 10 µl of each bacterial suspension (108 CFU/ml) on needle-like wounds on the stem base of three healthy leaf mustard plants (Singh et al. 2013). Control plants were treated with sterile distilled water. After inoculation, the plants were incubated at 28°C and 90% relative humidity in a growth chamber. This trial was repeated three times. All inoculated mustard stems were slightly water-soaked after 24 hours and eventually developed into soft rot symptoms, consistent with the original symptoms observed. The control plants remained symptom-free. The strains were re-isolated from inoculated plants and re-identified as P. brasiliense by sequencing five housekeeping genes, thus fulfilling Koch's postulates. P. brasiliense has a broad host range and has been reported on other Brassica species, such as Bok choy (Brassica rapa var. chinensis) in China (Li et al. 2023). Soft rot of leaf mustard caused by Pectobacterium aroidearum has also been reported previously (Chu et al. 2023). To our knowledge, this is the first report of P. brasiliense causing soft rot on leaf mustard in China. The soft rot poses a significant threat to the local leaf mustard industry and requires further research into epidemiology and disease management options.
ABSTRACT
PURPOSE: To identify rates of postoperative radiation therapy (RT) after breast conservation surgery (BCS) in women with stage I or II invasive breast cancer treated in Puerto Rico and to examine the sociodemographic and health services characteristics associated with variations in receipt of RT. METHODS: The Puerto Rico Central Cancer Registry-Health Insurance Linkage Database was used to identify patients diagnosed with invasive breast cancer between 2008 and 2012 in Puerto Rico. Claims codes identified the type of surgery and the use of RT. Logistic regression models were used to examine the independent association between sociodemographic and clinical covariates. RESULTS: Among women who received BCS as their primary definitive treatment, 64% received adjuvant RT. Significant predictors of RT after BCS included enrollment in Medicare (odds ratio [OR], 2.14; 95% CI, 1.46 to 3.13; P ≤ .01) and dual eligibility for Medicare and Medicaid (OR, 1.61; 95% CI, 1.14 to 2.27; P < .01). In addition, it was found that RT was more likely to have been received in certain geographic locations, including the Metro-North (OR, 2.20; 95% CI, 1.48 to 3.28; P < .01), North (OR, 1.78; 95% CI, 1.20 to 2.64; P < .01), West (OR, 4.04; 95% CI, 2.61 to 6.25; P < .01), and Southwest (OR, 2.79; 95% CI, 1.70 to 4.59; P < .01). Furthermore, patients with tumor size > 2.0 cm and ≤ 5.0 cm (OR, 0.61; 95% CI, 0.40 to 0.93; P = .02) and those with tumor size > 5.0 cm (OR, 0.37; 95% CI, 0.15 to 0.92; P = .03) were found to be significantly less likely to receive RT. CONCLUSION: Underuse of RT after BCS was identified in Puerto Rico. Patients enrolled in Medicare and those who were dually eligible for Medicaid and Medicare were more likely to receive RT after BCS compared with patients with Medicaid alone. There were geographic variations in the receipt of RT on the island.