First Report of Rust of Plumeria rubra Caused by Coleosporium plumeriae in Guangdong Province, China

Abstract

of the affected plants had small, brown, necrotic spots on most of the foliage. Yield losses of flowers of up to 20 to 30% were reported. The spots gradually enlarged, becoming irregular in shape, or remained circu lar, and with concentric rings or zones. In the later stages of infection, the spots coalesced, and the leaves withered, dried, and fell from the plants (4). A fungus was consistently isolated on potato dextrose agar (PDA) from the infected leaves of T. erecta. After 6 days of incubation at 26°C and a 12-h photoperiod, the fungus produced colonies that were flat, with a rough upper surface (2). The conidiophores were short. Conidia varied from 18 x 6 to 47 x 15 pm and were medium to dark brown or olivebrown in color, short beaked, borne in long chains, oval and bean shaped, with 1 to 5 transverse septa and 0 to 2 longitudinal septa. The rDNA of the internal transcribed spacer regions 1 and 2 and the 5.8S gene in seven isolates were amplified using primers ITS1 (5'-TCCGTAGGTGAACCTG CGG-3') and ITS4 (5'-TCCTCCGCTTATTGATATGC-3')-The nucleotide sequence was the same as isolate No. 7, which was deposited in GenBank (Accession No. KF307207). A BLAST search showed 97% identity with the strain Alternaria alternata GNU-F10 (KC752593). Seven isolates were also confirmed as A. alternata by PCR identification performed by spe cific primers (C_for/C_rev) of A. alternata (1). Seven isolates were grown on PDA for 2 weeks and the conidia harvested. A 5-pl drop of spore sus pension (1 x 105 spores/ml) was placed on each leaflet of 140 detached, surface-sterilized T. erecta leaves. Twenty leaves were inoculated with sterile distilled water as a control. The leaves were incubated in a growth chamber at 80 to 90% relative humidity, 50 to 60 klx/m2 light intensity, and a 12-h photoperiod. After 6 days, leaf spots similar to the original developed at inoculation sites for all isolates and A. alternata was consist ently re-isolated. The control leaves remained symptomless. The patho genicity test was performed three times. Leaf spot of T. erecta caused by Alternaria spp. is well known in Asian countries such as Japan (3). To our knowledge, this is the first report of A. alternata on T. erecta in the Bei jing district of China.

Integration of the metabolome and transcriptome reveals the molecular mechanism of drought tolerance in Plumeria rubra

“…Plumeria rubra is an ornamental tree species favored for planting in parks and gardens due to its brightly colored and fragrant flowers. It can grow normally in a strong light, high temperature, and shaded environment ( Yang et al, 2014 ). Panzhihua launched a pilot project in the typical dry-hot valley area of Hongge to investigate whether P. rubra can be used for the ecological restoration of rocky deserts.…”

New record of anthracnose disease in leaves of <em>Plumeria pudica</em> in Sri Lanka

“…P. pudica is currently widely cultivated as a cosmopolitan ornamental plant in Sri Lanka. Although foliar diseases such as anthracnose (Ismail et al, 2021) and rust (Yang et al, 2014 ) have been reported from other ornamental Plumeria species such as P. alba and P. rubra, respectively, reports on diseases in P. pudica are sparse. Powdery mildew caused by Erysiphe sp was reported in P. pudica leaves in United States in 2017.…”