Genetic Variability in Puccinia psidii Populations as Revealed by PCR-DGGE and T-RFLP Markers

Abstract

Eucalyptus rust caused by Puccinia psidii is responsible for losses of approximately 20% of young Eucalyptus plants, depending on the environmental conditions and the geographic location. Despite its economic importance, there are few studies describing the genetic variability in P. psidii populations that infect different host plants. In the present study, we evaluated the ribosomal DNA internal transcribed spacer region (rDNA-ITS) using polymerase chain reaction denaturing gradient gel electrophoresis and terminal restriction fragment length polymorphism to assess the genetic variability in P. psidii populations infecting different Eucalyptus spp. and hybrids, as well as guava, jabuticaba, and syzygium. These culture-independent methods were efficient in differentiating populations based on the host species from which they were collected. In general, the results from both techniques showed that the populations collected from guava, jabuticaba, and syzygium were different from and had a greater level of diversity than the Eucalyptus rust populations. The sequencing of cloned rDNA-ITS fragments confirmed that the vast majority of the profiles generated were from P. psidii. This analysis also revealed interesting single-nucleotide polymorphisms. Therefore, these culture-independent methods are suitable for the rapid assessment of genetic variability within and between populations of this biotrophic fungus on a variety of host species and could be a tool to study the evolution of this pathogen and its interactions with host plants.

Estudo molecular do desenvolvimento de <i>Puccinia psidii</i> Winter <i>in vitro</i> e no processo de infecção em<i> Eucalyptus grandis</i>

“…Estas características biológicas tornam estudos moleculares e genéticos de P. psidii mais difíceis. Embora muito avanços foram alcançados em pesquisas sobre a diversidade genética, estrutura da população de P. psidii e interação com o hospedeiro (GLEN et al, 2007;QUECINE et al, 2014;SANDHU, et al, 2016), conhecimentos sobre a biologia das ferrugens e os genes envolvidos no processo inicial de infecção e crescimento destes patógenos ainda são limitados (CHEN et al, 1993;FIGUEIREDO et al, 2008;LORYS et al, 2002;ZHANG et al, 2008 utilizadas para a manutenção e a multiplicação do isolado MF-1 como descrito por Leite et al (2013). Vários genes importantes e relacionados ao reconhecimento, germinação, diferenciação e patogenicidade de fungos vêm sendo identificados e descritos ultimamente na literatura (AHN et al, 2003;KIM et al, 2004;ZHANG et al, 2008).…”

“…psidii ataca várias mirtáceas comprometendo a biodiversidade de plantas nativas (CARNEGIE, 2015;COUTINHO et al, 1998;GLEN et al, 2007;WALSH;MACBETH, 2006;JUNGHANS et al, 2003;LANGRELL;ALFENAS, 2008;QUECINE et al, 2014;TOMMERUP;OLD, 2003).…”

Identificação <i>in silico</i> e perfil transcricional de genes candidatos a efetores de <i>Austropuccinia psidii</i>

“…De acordo com o estilo de vida podem ser classificados como necrotróficos, hemibiotróficos e biotróficos (Agrios, 2005). Os fungos biotróficos obtêm seus nutrientes de células vivas do hospedeiro, sendo inteiramente dependentes do mesmo para crescimento e reprodução (Catanzariti et al, 2006), dessa forma, seu estudo torna-se muito mais laborioso devido à dificuldade de cultivá-los in vitro (Quecine et al, 2014).…”

Deciphering the role of early molecular interactions between >i<Eucalyptus>/i< spp. x >i<Austropuccinia psidii>/i< and its pathogenesis

“…psidii, little is known about genetic variability in pathogen populations and its correlation with the degree of host susceptibility (Quecine et al, 2014, Santos et al, 2019. Furthermore, there are no reports about the successful multiplication of uredospores in culture medium, hampering the molecular studies of this pathogen.…”

“…The inter-intra specific genetic variability for resistance to rust in eucalyptus species allows the control of disease through clones, progenies and resistant species (Silva et al, 2014). However, the selection of resistant progenies from eucalyptus clones has been a challenge for forest industry and particular importance to eucalyptus breeding programs (Quecine et al, 2014). Little is known about the life cycle of A. psidii, which is essential to predict evolutionary potential and developing control strategies, as creation of durable host resistance or the removal of alternative hosts (Billiard et al, 2012;Mcdonald and Linde, 2002).…”