Publicações

@article{Silva2021,

title = {Effects of Deficit Irrigation and Huanglongbing on Sweet Orange Trees},

author = {Jefferson Rangel Silva and Rodrigo Marcelli Boaretto and Jéssica Aparecida Lara Lavorenti and Bruna Castriani Ferreira Santos and Helvecio Della Coletta-Filho and Dirceu Mattos},

doi = {10.3389/FPLS.2021.731314/BIBTEX},

issn = {1664462X},

year  = {2021},

date = {2021-01-01},

journal = {Frontiers in Plant Science},

volume = {12},

pages = {2228},

publisher = {Frontiers Media S.A.},

abstract = {This study addresses the interactive effects of deficit irrigation and huanglongbing (HLB) infection on the physiological, biochemical, and oxidative stress responses of sweet orange trees. We sought to answer: (i) What are the causes for the reduction in water uptake in HLB infected plants? (ii) Is the water status of plants negatively affected by HLB infection? (iii) What are the key physiological traits impaired in HLB-infected plants? and (iv) What conditions can mitigate both disease severity and physiological/biochemical impairments in HLB-infected plants? Two water management treatments were applied for 11 weeks to 1-year-old-trees that were either healthy (HLB–) or infected with HLB (+) and grown in 12-L pots. Half of the trees were fully irrigated (FI) to saturation, whereas half were deficit-irrigated (DI) using 40% of the water required to saturate the substrate. Our results demonstrated that: reduced water uptake capacity in HLB+ plants was associated with reduced root growth, leaf area, stomatal conductance, and transpiration. Leaf water potential was not negatively affected by HLB infection. HLB increased leaf respiration rates (ca. 41%) and starch synthesis, downregulated starch breakdown, blocked electron transport, improved oxidative stress, and reduced leaf photosynthesis (ca. 57%) and photorespiration (ca.57%). Deficit irrigation reduced both leaf respiration (ca. 45%) and accumulation of starch (ca.53%) by increasing maltose (ca. 20%), sucrose, glucose, and fructose contents in the leaves, decreasing bacterial population (ca. 9%) and triggering a series of protective measures against further impairments in the physiology and biochemistry of HLB-infected plants. Such results provide a more complete physiological and biochemical overview of HLB-infected plants and can guide future studies to screen genetic tolerance to HLB and improve management strategies under field orchard conditions.},

keywords = {Greening, leaf respiration, leaf water potential, Oxidative stress, photorespiration, photosynthesis, starch metabolism},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Following the effects of micronutrient supply in HLB-infected trees: plant responses and ‘Candidatus Liberibacter asiaticus’ acquisition by the Asian citrus psyllid},

author = {Jefferson Rangel Silva and Fausto Veiga Alvarenga and Rodrigo Marcelli Boaretto and João Roberto Spotti Lopes and José Antônio Quaggio and Helvecio Della Coletta Filho and Dirceu Mattos},

url = {https://link.springer.com/article/10.1007/s40858-020-00370-9},

doi = {10.1007/S40858-020-00370-9/FIGURES/3},

issn = {19832052},

year  = {2020},

date = {2020-01-01},

journal = {Tropical Plant Pathology},

volume = {45},

issue = {6},

pages = {597-610},

publisher = {Springer Science and Business Media Deutschland GmbH},

abstract = {Despite efforts of research to establish best nutrient management practices in HLB-affected citrus orchards, there are still doubts about the contribution of such strategies to minimizing losses caused by the disease in the citrus industry. We evaluated the effects of micronutrient (Zn, Mn, and/or Cu) supply and ‘Candidatus Liberibacter asiaticus’ (CLas) infection on physiological and growth traits of sweet orange trees (Citrus sinensis (L.) Osbeck)) to understand if enhanced micronutrient supply would improve the growth of plants infected with CLas and reduce bacterial infection, as well as the acquisition of CLas by adults and nymphs of Diaphorina citri, correlated with nutritional status of trees. Plants were either grafted with buds obtained from micrografted plants (healthy, −) or buds infected with CLas (diseased plants, +). Infected plants were exposed to one of the five nutrient treatments, applied to leaf and root: (i) nilZnMnCu+: not fertilized with Cu, Mn, and Zn; (ii) Zn+: fertilized with zinc sulfate (ZnSO4.H2O); (iii) Mn+: fertilized with manganese sulfate (MnSO4.H2O); (iv) Cu+: fertilized with copper hydroxide [Cu(OH)2]; and (v) ZnMnCu+: fertilized with all three micronutrients. Likewise, healthy plants were exposed to one of the two treatments as above: (i) nilZnMnCu− or (v) ZnMnCu−. We found that CLas impairs plant biomass production regardless of nutrient treatments, especially root growth, and increases specific leaf dry weight as disease progresses because of starch accumulation. Moreover, individual supply with Zn, Mn, or Cu can mitigate such deleterious effects of HLB on starch metabolism. HLB also changes nutrient concentrations in both leaves and sap extract, regardless of nutrient treatments, although treatments do not reduce the CLas titer in plants as determined by RT-qPCR. On the contrary, micronutrients applied in combination (ZnMnCu+) can reduce the acquisition of CLas by adults and especially nymphs of D. citri, likely reducing the disease infection in citrus orchards.},

keywords = {Bacteria acquisition, Citrus, Copper, Greening, huanglongbing, Manganese, Starch content, Zinc},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Following the effects of micronutrient supply in HLB-infected trees: plant responses and ‘Candidatus Liberibacter asiaticus’ acquisition by the Asian citrus psyllid},

author = {Jefferson Rangel Silva and Fausto Veiga Alvarenga and Rodrigo Marcelli Boaretto and João Roberto Spotti Lopes and José Antônio Quaggio and Helvecio Della Coletta Filho and Dirceu Mattos},

url = {https://link.springer.com/article/10.1007/s40858-020-00370-9},

doi = {10.1007/S40858-020-00370-9/FIGURES/3},

issn = {19832052},

year  = {2020},

date = {2020-01-01},

journal = {Tropical Plant Pathology},

volume = {45},

issue = {6},

pages = {597-610},

publisher = {Springer Science and Business Media Deutschland GmbH},

abstract = {Despite efforts of research to establish best nutrient management practices in HLB-affected citrus orchards, there are still doubts about the contribution of such strategies to minimizing losses caused by the disease in the citrus industry. We evaluated the effects of micronutrient (Zn, Mn, and/or Cu) supply and ‘Candidatus Liberibacter asiaticus’ (CLas) infection on physiological and growth traits of sweet orange trees (Citrus sinensis (L.) Osbeck)) to understand if enhanced micronutrient supply would improve the growth of plants infected with CLas and reduce bacterial infection, as well as the acquisition of CLas by adults and nymphs of Diaphorina citri, correlated with nutritional status of trees. Plants were either grafted with buds obtained from micrografted plants (healthy, −) or buds infected with CLas (diseased plants, +). Infected plants were exposed to one of the five nutrient treatments, applied to leaf and root: (i) nilZnMnCu+: not fertilized with Cu, Mn, and Zn; (ii) Zn+: fertilized with zinc sulfate (ZnSO4.H2O); (iii) Mn+: fertilized with manganese sulfate (MnSO4.H2O); (iv) Cu+: fertilized with copper hydroxide [Cu(OH)2]; and (v) ZnMnCu+: fertilized with all three micronutrients. Likewise, healthy plants were exposed to one of the two treatments as above: (i) nilZnMnCu− or (v) ZnMnCu−. We found that CLas impairs plant biomass production regardless of nutrient treatments, especially root growth, and increases specific leaf dry weight as disease progresses because of starch accumulation. Moreover, individual supply with Zn, Mn, or Cu can mitigate such deleterious effects of HLB on starch metabolism. HLB also changes nutrient concentrations in both leaves and sap extract, regardless of nutrient treatments, although treatments do not reduce the CLas titer in plants as determined by RT-qPCR. On the contrary, micronutrients applied in combination (ZnMnCu+) can reduce the acquisition of CLas by adults and especially nymphs of D. citri, likely reducing the disease infection in citrus orchards.},

keywords = {Bacteria acquisition, Citrus, Copper, Greening, huanglongbing, Manganese, Starch content, Zinc},

pubstate = {published},

tppubtype = {article}

}

@article{Morelli2020,

title = {Impact of HLB on the physiological quality of citrus rootstock seeds and non-vertical ‘Candidatus Liberibacter asiaticus’ transmission},

author = {Marília Morelli and Felipe Hirayuki Takayassu and Camilla Andrade Pacheco and Patrícia Marluci Conceição and Helvécio Della Coletta Filho and Fernando Alves Azevedo},

url = {https://link.springer.com/article/10.1007/s40858-020-00371-8},

doi = {10.1007/S40858-020-00371-8/METRICS},

issn = {19832052},

year  = {2020},

date = {2020-01-01},

journal = {Tropical Plant Pathology},

volume = {45},

issue = {6},

pages = {620-625},

publisher = {Springer Science and Business Media Deutschland GmbH},

abstract = {Huanglongbing (HLB) is the main disease of citriculture worldwide, being mainly caused by the bacterium known as ‘Candidatus Liberibacter asiaticus’ (CLas), limited to the phloem and naturally transmitted by vector insects known as psyllids. For the production of citrus seedlings, it is necessary to use rootstocks that are propagated by seeds from fruits produced by mother plants grown in field, however being submitted to natural HLB transmission. Although there is no evidence of CLas transmission from seeds to seedlings, little is known about the effects of this bacterium on the physiological quality of seeds obtained from CLas-infected plants. Therefore, the aim of this work was to evaluate the physiological quality of seeds from ‘Rangpur’ lime and ‘Swingle’ citrumelo rootstocks, from CLas-infected plants, with symptomatic and asymptomatic branches. The parameters evaluated, in addition to fruit development in mother plants, were germination rate, tetrazolium test, electrical conductivity, seedling emergence in greenhouse, and vegetative development and molecular analysis via qPCR for the detection of bacteria (leaf petiole, fruit peduncles, roots, seed coats, and seed endosperm). The presence of CLas in plants of both rootstocks has negative impact on fruit development, as well as on the number of normal seeds. In addition, there is reduced germination and seed emergence. Although CLas was detected in different tissues (leaf petiole, fruit peduncles and seed coat, and seed embryo), no vertical bacteria transmission was detected. Results have shown that seeds from CLas-infected branches have impaired physiological quality, but without bacterial transmission from seeds to seedlings.},

keywords = {‘Rangpur’ lime, ‘Swingle’ citrumelo, bacterium, Citrus, Greening, Seeds},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Genetic diversity of ‘Candidatus Liberibacter asiaticus’ in Brazil analyzed in different geographic regions and citrus varieties},

author = {Larissa Bonevaes Paula and Hong Lin and Eduardo Sanches Stuchi and Carolina Sardinha Francisco and Nágela Gomes Safady and Helvécio Della Coletta-Filho},

url = {https://link.springer.com/article/10.1007/s10658-019-01695-1},

doi = {10.1007/S10658-019-01695-1/METRICS},

issn = {15738469},

year  = {2019},

date = {2019-01-01},

journal = {European Journal of Plant Pathology},

volume = {154},

issue = {4},

pages = {863-872},

publisher = {Springer Netherlands},

abstract = {The bacterium ‘Candidatus Liberibacter asiaticus’ - CLas, the agent associated with citrus huanglongbing disease was first reported in Sao Paulo State in 2004 and has spread throughout the citrus-growing regions of Sao Paulo and further to the states of Minas Gerais and Parana. However, little information is available regarding the genetic diversity of CLas since its introduction. Understanding the genetic diversity of this bacterium is important for tracing migration routes and for identifying evolutionary selection forces that may affect the genetic diversity of this pathogen. Total DNA from 199 HLB-diseased citrus species trees was sampled from geographic regions in Sao Paulo, Parana and Minas Gerais states and the CLas isolates were genotyped by simple sequence DNA repeats (SSR). Nei’s genetic diversity index was observed to be low in all populations (HNei = 0.11–0.26). Wright’s fixation index (FST), which measures population genetic differentiation, did not differ significantly between CLas populations from Sao Paulo State and from Minas Gerais, but significant values (FST = 0.118–0.191) of the Parana CLas population distinguish it from the others. Interestingly, higher values (FST = 0.275–0.445) were observed for the CLas populations obtained from different citrus species compared to sweet orange, suggesting that the citrus genotypes could be driven the genetic diversity of CLas. Clustering analysis supports the FST results that split the CLas samples into three genetically distinct populations. These results indicate that genetically homogeneous populations of CLas infect sweet orange plants in various regions of Sao Paulo State and Minas Gerais, but not Parana, suggesting that different introduction events may have occurred for the Sao Paulo and Parana states.},

keywords = {Citrus pathogen, genetic diversity, Greening, SSR},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Genetic diversity of ‘Candidatus Liberibacter asiaticus’ in Brazil analyzed in different geographic regions and citrus varieties},

author = {Larissa Bonevaes Paula and Hong Lin and Eduardo Sanches Stuchi and Carolina Sardinha Francisco and Nágela Gomes Safady and Helvécio Della Coletta-Filho},

url = {https://link.springer.com/article/10.1007/s10658-019-01695-1},

doi = {10.1007/S10658-019-01695-1/METRICS},

issn = {15738469},

year  = {2019},

date = {2019-01-01},

journal = {European Journal of Plant Pathology},

volume = {154},

issue = {4},

pages = {863-872},

publisher = {Springer Netherlands},

abstract = {The bacterium ‘Candidatus Liberibacter asiaticus’ - CLas, the agent associated with citrus huanglongbing disease was first reported in Sao Paulo State in 2004 and has spread throughout the citrus-growing regions of Sao Paulo and further to the states of Minas Gerais and Parana. However, little information is available regarding the genetic diversity of CLas since its introduction. Understanding the genetic diversity of this bacterium is important for tracing migration routes and for identifying evolutionary selection forces that may affect the genetic diversity of this pathogen. Total DNA from 199 HLB-diseased citrus species trees was sampled from geographic regions in Sao Paulo, Parana and Minas Gerais states and the CLas isolates were genotyped by simple sequence DNA repeats (SSR). Nei’s genetic diversity index was observed to be low in all populations (HNei = 0.11–0.26). Wright’s fixation index (FST), which measures population genetic differentiation, did not differ significantly between CLas populations from Sao Paulo State and from Minas Gerais, but significant values (FST = 0.118–0.191) of the Parana CLas population distinguish it from the others. Interestingly, higher values (FST = 0.275–0.445) were observed for the CLas populations obtained from different citrus species compared to sweet orange, suggesting that the citrus genotypes could be driven the genetic diversity of CLas. Clustering analysis supports the FST results that split the CLas samples into three genetically distinct populations. These results indicate that genetically homogeneous populations of CLas infect sweet orange plants in various regions of Sao Paulo State and Minas Gerais, but not Parana, suggesting that different introduction events may have occurred for the Sao Paulo and Parana states.},

keywords = {Citrus pathogen, genetic diversity, Greening, SSR},

pubstate = {published},

tppubtype = {article}

}