Murraya paniculata and Related Species as Potential Hosts and Inoculum Reservoirs of ‘Candidatus Liberibacter asiaticus’, Causal Agent of Huanglongbing

Abstract

Huanglongbing (HLB), considered to be the most serious insect-vectored bacterial disease of citrus, is transmitted in nature by the Asian citrus psyllid Diaphorina citri and the African citrus psyllid Trioza erytreae. D. citri was discovered in southern Florida in 1998 and the HLB disease in 2005. Both have become established throughout citrus-producing areas of Florida. Murraya species are widely grown in southern Florida as ornamental hedges and are readily colonized by D. citri vectors. Colonies of D. citri, isolates of ‘Candidatus Liberibacter asiaticus’ from Taiwan and Florida, and the Murraya species were established in the BSL-3 biosecurity facility at Fort Detrick. In controlled inoculation experiments, D. citri transmitted ‘Ca. L. asiaticus’ into M. paniculata (34/36 plants) and M. exotica (22/23 plants), but not into Bergera (Murraya) koenigii. Disease symptoms rarely developed in Murraya plants; however, positive infections were determined by conventional and real-time polymerase chain reaction (PCR). Back-inoculations of ‘Ca. L. asiaticus’ from M. paniculata to Madam Vinous sweet orange resulted in disease development in 25% of the inoculated plants. Considerable variability was observed in infection rates, titer, and persistence of ‘Ca. L. asiaticus’ in infected Murraya.

Live Population Dynamics of ‘Candidatus Liberibacter asiaticus’, the Bacterial Agent Associated with Citrus Huanglongbing, in Citrus and Non-Citrus Hosts

“…L. asiaticus' cells/psyllid). In order to serve as an inoculum reservoir, a plant species should be able to retain the pathogen in an infectious state over an extended period of time (4). Our data showed that 'Ca.…”

“…L. asiaticus'-infected S. buxifolia plants in pathways 2 and 3 were colonized by healthy psyilids. During the AAP, psyllids could mate and reproduce but only adults were used for inoculations (4,26). When new flushes were available on receptor plants for psyllid feeding, 10 psylhds from source plants were collected and transferred onto one receptor plant for at least 14 days of inoculation access period (IAP; 4).…”

“…Studies have shown that 'Ca. L. asiaticus' could be detected in some citrus relatives; for example, Murraya panictdata (4,5,36), Clausena lansittm (5,7), and Litnonia acidissinia L. (16,19). However, most of the studies were mainly diagnostic work with field samples (5-7).…”

Intragenomic homogeneity on Liberibacter 16S rDNA confirms phylogeny and explains ecological strategy

“…Las has been reported to exist in a number of genetic groupings, depending on the DNA segment analysed [20] and the divergence on other DNA segments may be more useful for epidemiological purposes. Las is also known from close citrus relatives commonly grown for ornamental and culinary purposes, especially Murraya species [21][22][23].…”

Biologia em temperaturas alternantes e exigências térmicas de <i>Diaphorina citri</i> Kuwayama, 1908 (Hemiptera: Liviidae) e <i>Tamarixia radiata</i> (Waterston, 1922) (Hymenoptera: Eulophidae) visando ao seu zoneamento em regiões citrícolas do estado

“…Para as espécies que ocorrem no Brasil, Lopes et al (2009) (DAMSTEEGT et al, 2010). Gasparoto et al (2010) confirmaram a transmissão de Ca.…”