Publications

@article{Hippler2018c,

title = {Oxidative stress induced by Cu nutritional disorders in Citrus depends on nitrogen and calcium availability},

author = {Franz Walter Rieger Hippler and Rodrigo Marcelli Boaretto and Veronica Lorena Dovis and José Antônio Quaggio and Ricardo Antunes Azevedo and Dirceu Mattos-Jr},

url = {https://www.nature.com/articles/s41598-018-19735-x},

doi = {10.1038/s41598-018-19735-x},

issn = {2045-2322},

year  = {2018},

date = {2018-01-01},

journal = {Scientific Reports 2018 8:1},

volume = {8},

issue = {1},

pages = {1-13},

publisher = {Nature Publishing Group},

abstract = {Nutritional stress caused by copper (Cu) deficiency or toxicity affects fruit production of citrus orchards worldwide, but this could be minimised by fine-tuned fertilisation in the orchards. Two experiments were performed aiming to evaluate the photosynthetic capacity and the antioxidant enzyme activities of Swingle citrumelo seedlings, grown in nutrient solution (NS) with two levels of nitrogen (N) in the first experiment (adequate-N and high-N) and two levels of calcium (Ca) in the second (low-Ca and adequate-Ca). Plants were then exposed to various Cu levels (low, medium and high) for 15 days. Plants under Cu-toxicity exhibited specific effects on reactive oxygen species formation and root-to-shoot plant signalling. Copper absorption was greater with increased Cu concentration in the NS, which reduced plant biomass accumulation, gas exchange measurements, the activity of nitrate reductase and affected Cu partitioning between roots and shoots. Despite these effects, oxidative stress induced by excess-Cu was reduced at the highest N dose when compared to control and, on the contrary, increased with low-Ca supply. Therefore, a rational supply of N or Ca minimises Cu-induced stress damages to roots and leaves of plants, by directly enhancing the antioxidant system and protecting the associated antioxidative enzyme activities, whilst maintaining photosynthesis.},

keywords = {Abiotic, Plant physiology},

pubstate = {published},

tppubtype = {article}

}

@article{Moreira2018,

title = {Selection and validation of reference genes for quantitative gene expression analyses in various tissues and seeds at different developmental stages in Bixa orellana L.},

author = {Viviane S. Moreira and Virgínia L. F. Soares and Raner J. S. Silva and Aurizangela O. Sousa and Wagner C. Otoni and Marcio G. C. Costa},

url = {https://link.springer.com/article/10.1007/s12298-018-0528-1},

doi = {10.1007/S12298-018-0528-1},

issn = {0974-0430},

year  = {2018},

date = {2018-01-01},

journal = {Physiology and Molecular Biology of Plants 2018 24:3},

volume = {24},

issue = {3},

pages = {369-378},

publisher = {Springer},

abstract = {Bixa orellana L., popularly known as annatto, produces several secondary metabolites of pharmaceutical and industrial interest, including bixin, whose molecular basis of biosynthesis remain to be determined. Gene expression analysis by quantitative real-time PCR (qPCR) is an important tool to advance such knowledge. However, correct interpretation of qPCR data requires the use of suitable reference genes in order to reduce experimental variations. In the present study, we have selected four different candidates for reference genes in B. orellana, coding for 40S ribosomal protein S9 (RPS9), histone H4 (H4), 60S ribosomal protein L38 (RPL38) and 18S ribosomal RNA (18SrRNA). Their expression stabilities in different tissues (e.g. flower buds, flowers, leaves and seeds at different developmental stages) were analyzed using five statistical tools (NormFinder, geNorm, BestKeeper, ΔCt method and RefFinder). The results indicated that RPL38 is the most stable gene in different tissues and stages of seed development and 18SrRNA is the most unstable among the analyzed genes. In order to validate the candidate reference genes, we have analyzed the relative expression of a target gene coding for carotenoid cleavage dioxygenase 1 (CCD1) using the stable RPL38 and the least stable gene, 18SrRNA, for normalization of the qPCR data. The results demonstrated significant differences in the interpretation of the CCD1 gene expression data, depending on the reference gene used, reinforcing the importance of the correct selection of reference genes for normalization.},

keywords = {Biological and Medical Physics, Biophysics, Cell Biology, Plant physiology, Plant Sciences},

pubstate = {published},

tppubtype = {article}

}

@article{Neves2017,

title = {Recurrent water deficit causes epigenetic and hormonal changes in citrus plants},

author = {Diana Matos Neves and Lucas Aragão Da Hora Almeida and Dayse Drielly Souza Santana-Vieira and Luciano Freschi and Claudia Fortes Ferreira and Walter Dos Santos Soares Filho and Marcio Gilberto Cardoso Costa and Fabienne Micheli and Maurício Antônio Coelho Filho and Abelmon Da Silva Gesteira},

url = {https://www.nature.com/articles/s41598-017-14161-x},

doi = {10.1038/s41598-017-14161-x},

issn = {2045-2322},

year  = {2017},

date = {2017-01-01},

journal = {Scientific Reports 2017 7:1},

volume = {7},

issue = {1},

pages = {1-11},

publisher = {Nature Publishing Group},

abstract = {The present study evaluated the physiological, molecular and hormonal parameters from scion/rootstock interaction of citrus plants during recurrent water deficit. Responses of the Valencia (VO) scion variety grafted on two rootstocks with different soil water extraction capacities, Rangpur Lime (RL) and Sunki Maravilha (SM), during three successive periods of water deficit: plants exposed to a single episode of water deficit (WD1) and plants exposed to two (WD2) and three (WD3) recurrent periods of WD were compared. The combinations VO/RL and VO/SM presented polymorphic alterations of epigenetic marks and hormonal (i.e. abscisic acid, auxins and salicylicacid) profiles, which were particularly prominent when VO/SM plantswere exposed toWD3 treatment. Upon successive drought events, the VO/SM combination presented acclimatization characteristics that enable higher tolerance to water deficit by increasing transpiration (E), stomatal conductance (g s ) and photosynthetic rate (A), which in turn may have facilitated the whole plant survival. Besides providing comprehensive data on the scion/rootstock interactions upon successive stress events, this study brings the first dataset suggesting that epigenetic alterations in citrus plants triggered by recurrent water deficit lead to improved drought tolerance in this crop species.},

keywords = {drought, Plant physiology},

pubstate = {published},

tppubtype = {article}

}

@article{Zambrosi2017,

title = {Anatomical and ultrastructural damage to citrus leaves from phosphite spray depends on phosphorus supply to roots},

author = {Fernando C. B. Zambrosi and Geisa L. Mesquita and Gillyade Menino and Francisco A. O. Tanaka and Dirceu Mattos and Jose A. Quaggio},

url = {https://link.springer.com/article/10.1007/s11104-017-3314-x},

doi = {10.1007/S11104-017-3314-X},

issn = {1573-5036},

year  = {2017},

date = {2017-01-01},

journal = {Plant and Soil 2017 418:1},

volume = {418},

issue = {1},

pages = {557-569},

publisher = {Springer},

abstract = {Although phosphite (PO3, Phi) cannot replace phosphate (PO4, Pi) as a nutritional source of phosphorus (P) for plants, decisions about using foliar Phi application in citrus groves scarcely take into account P availability and plant nutritional status. Accordingly, we studied the interactive effects of P supply in the rooting medium and foliar sprays of Pi or Phi on citrus tree performance and leaf anatomy and ultrastructure. Young sweet orange trees were grown hydroponically using P-deficient (PD) or P-sufficient (PS) nutrient solutions for 15 weeks in combination with 3 foliar spray treatments: 0.16 M P in the form of Pi (KH2PO4) or Phi (KH2PO3) and a control spray of 0.16 M potassium chloride (KCl). Six foliar sprays were applied to the drip point at 15-day intervals during the experimental period. Before the trees were harvested to estimate growth, mature leaves were sampled to study the anatomical and ultrastructural organization and to evaluate P concentration. Under PD, the Pi spray stimulated tree growth compared with the control, whereas Phi sprays impaired tree performance, suggesting toxic effects. Both Pi and Phi applications increased the leaf P concentration relative to that of the control. Leaves of PD trees exposed to Phi exhibited pronounced damage to the epidermis, and stomata showed deformed ostioles and surface flaking. Moreover, phloem and xylem vessels were disorganized, cell wall presented sinuosity, cell membranes were plasmolyzed, and chloroplast thylakoids were disrupted, with accumulation of starch and plastoglobuli. However, no similar changes were observed either in PD trees under Pi spray or in PS trees independent of foliar treatment. PD trees receiving KCl exhibited intermediate responses between those of Pi and Phi applications. This was the first study to demonstrate that Phi spray disrupts the anatomical and ultrastructural organization of citrus leaves under P deficiency. Our results provide insights into the mechanisms explaining the poor nutritional value of Phi and support information to guide the use of Phi-based products.},

keywords = {Ecology, Plant physiology, Plant Sciences, Soil Science & Conservation, Starch, Stomata},

pubstate = {published},

tppubtype = {article}

}