Humic acids induce the expression of nitrate transporters in passion-fruit seedlings/Acidos humicos induzem a expressao dos transportadores de nitrato em mudas de maracujazeiro

• Published in: Revista Brasileira de fruticultura Vol. 45; no. 3
• Main Authors: Filho, Paulo Fernando Marques Cavalcanti, Baia, Daiane Carvalho, Ribeiro, Rafael Chaves, Rosa, Raul Castro Carrielo, Canellas, Luciano Pasqualoto
• Format: Journal Article
• Language: Portuguese
• Published: Sociedade Brasileira de Fruticultura 01-05-2023
• Subjects: Adenosine triphosphatase; Castor oil; Fertilizer industry; Genetic research; Genetic transcription; Humic acid; Organic fertilizers; Physiological aspects; Urea
• ISSN: 0100-2945
• DOI: 10.1590/0100-29452023941

The management of organic fertilization in passion fruit has been carried out empirically based on the responses of the crops and the experience of farmers. Knowledge of the physiological responses of plants to organic fertilizers is essential to optimize fertilization programs. The objective of this study was to evaluate the differential expression of genes coding for nitrate transporters as well as plasma membrane [H.sup.+]-ATPase in passion fruit seedlings treated with different organic fertilizers in the presence or not of humic acids. The equivalent of one gram of total nitrogen dissolved in water from cattle manure, castor oil cake and urea were added and the seedlings were treated or not with a suspension of humic acids (2 mmol/L). Differential expression of low and high affinity nitrate transporters (PeNRT2.2 and PeNRT1.1 PeNRT2.2e) and [H.sup.+]-ATPase (PeMha) was performed by qRT-PCR. The use of cattle manure increased the differential expression of the high affinity transporter regarding to the control. The application of humic acids amplified the increase observed in the differential transcription of the high-affinity transporter with manure and urea fertilization, with no effect observed with the use of castor oil cake. Humic acids induced transcription of the gene encoding [H.sup.+]-ATPases in all treatments compared to control. The application of biofertilizer based on humic acids in low concentrations directly on the plant can be used with the objective of optimizing the organic fertilization of passion fruit with cattle manure and urea. Index Terms: organic fertilizers, physiological responses, NRT genes, H+-ATPase. O manejo da adubacao organica no maracujazeiro tem sido realizado de forma empirica, baseado nas respostas das lavouras e na experiencia do produtor. O conhecimento das respostas fisiologicas da planta a adubacao organica e fundamental para otimizar os programas de fertilizacao. O objetivo deste trabalho foi avaliar a expressao diferencial dos transportadores de nitrato bem como da [H.sup.+]-ATPase de membrana plasmatica, em mudas de maracujazeiro adubadas com diferentes fertilizantes organicos, na presenca ou nao de acidos humicos. Foram adicionados o equivalente a um grama de nitrogenio total dissolvido em agua proveniente de esterco de curral, torta de mamona e ureia, e as mudas foram tratadas ou nao com uma suspensao de acidos humicos (2 mmol/L). A expressao diferencial dos transportadores de nitrato, de baixa e de alta afinidade PeNRT2.2) e da [H.sup.+]-ATPase, foi realizada por qRT-PCR. O uso de esterco de curral aumentou a expressao diferencial do transportador de alta afinidade em relacao ao controle. A aplicacao de acidos humicos ampliou o aumento observado na transcricao diferencial do transportador de alta afinidade com a adubacao com esterco e tambem com ureia, nao sendo observado qualquer efeito com o uso da torta de mamona. Os acidos humicos induziram a transcricao do gene que codifica a [H.sup.+]-ATPases em todos os tratamentos, em relacao ao controle. A aplicacao de acidos humicos em baixas concentracoes, diretamente sobre a planta, pode ser utilizada com o objetivo de otimizar a adubacao organica do maracujazeiro quando realizada com esterco de curral e tambem com ureia. Termos de Indexacao: NTD, Fertilizacao organica, Genes NRT, ATPase.