Genome-Wide Identification and Expression Analysis of JAZ Family Involved in Hormone and Abiotic Stress in Sweet Potato and Its Two Diploid Relatives

Jasmonate ZIM-domain (JAZ) proteins are key repressors of a jasmonic acid signaling pathway. They play essential roles in the regulation of plant growth and development, as well as environmental stress responses. However, this gene family has not been explored in sweet potato. In this study, we identified 14, 15, and 14 JAZs in cultivated hexaploid sweet potato (Ipomoea batatas, 2n = 6x = 90), and its two diploid relatives Ipomoea trifida (2n = 2x = 30) and Ipomoea triloba (2n = 2x = 30), respectively. These JAZs were divided into five subgroups according to their phylogenetic relationships with Arabidopsis. The protein physiological properties, chromosome localization, phylogenetic relationship, gene structure, promoter cis-elements, protein interaction network, and expression pattern of these 43 JAZs were systematically investigated. The results suggested that there was a differentiation between homologous JAZs, and each JAZ gene played different vital roles in growth and development, hormone crosstalk, and abiotic stress response between sweet potato and its two diploid relatives. Our work provided comprehensive comparison and understanding of the JAZ genes in sweet potato and its two diploid relatives, supplied a theoretical foundation for their functional study, and further facilitated the molecular breeding of sweet potato.

Avaliação do potencial alelopático e fitotoxicidade de Hymenaea stigonocarpa em espécies invasoras e cultivadas

O Cerrado é um hotspot mundial de biodiversidade e vem sofrendo com a expansão das áreas destinadas à produção de commodities. Mais da metade de sua área foi desmatada ou transformada por ação antrópica, incluindo a introdução e/ou expansão de plantas oportunistas. Atualmente, inúmeras espécies se tornaram invasoras de ambientes naturais do bioma. Buscando mitigar este processo invasivo, a utilização de espécies nativas que inibam o desenvolvimento das plantas invasoras e ao mesmo tempo favoreçam a biodiversidade nativa representa uma estratégia promissora. Dessa forma, este estudo avaliou o potencial alelopático da rizosfera de plântulas de Hymenaea stigonocarpa (jatobá-do-cerrado) na germinação e crescimento inicial das espécies invasoras, Megathyrsus maximus e Ipomoea triloba, e da cultivada, Sesamum indicum, plantadas em solo previamente ocupado por plântulas de jatobá-do-cerrado. Ademais, avaliou-se o efeito fitotóxico do extrato aquoso de suas raízes em coleóptilos de Triticum aestivum, usando o percentual de inibição do seu crescimento. As espécies alvo plantadas em solo previamente ocupado por plântulas de jatobá-do-cerrado apresentaram inibição significativa do crescimento em comparação ao controle. A inibição do crescimento de S. indicum foi de 31% da parte aérea e de 48% da radicular; enquanto M. maximum teve inibição de 41 e 84%, respectivamente. Já I. triloba não germinou. Contudo, não se observou alteração significativa do alongamento dos coleóptilos de T. aestivum expostos ao extrato de jatobá-do-cerrado. Os resultados obtidos sugerem potencial atividade alelopática desta nativa sobre plantas daninhas, indicando seu uso como estratégia em processos de recuperação de áreas degradadas do Cerrado com o benefício de controlar o desenvolvimento de invasoras.

Efficacy and interaction of dicamba-haloxyfop tank mixtures

The application of herbicide tank mixtures is a common practice in agricultural settings, especially for controlling weed communities with mono and eudicotyledons species occurring simultaneously. Therefore, thisstudy was carried out with the objective of evaluating the effectiveness and interaction of dicamba-haloxyfop tank mixtures used to control four weed species. For this, four different experiments were conducted, each with one of the plant species, namely: sourgrass (Digitaria insularis), horseweed (Conyza spp.), morning glory (Ipomoea triloba) and goosegrass (Eleusine indica). In each experiment, the experimental design consisted of completely randomized blocks, in a 4x4 factorial scheme of treatments, totaling 16 treatments with five replications, i.e., 80 plots of each species. Four doses of the herbicide dicamba (480, 240, 120 and 0 g ha-1) and four doses of the herbicide haloxyfop (60, 30, 15 and 0 g ha-1) were adopted. Percentage control was evaluated at 14 and 28 days after application (DAA) and mass of dry matter was evaluated at 28 DAA. Antagonistic, additive and synergistic effects were observed for dicamba-haloxyfop tank mixtures, with a greater preponderance of additive effects. Considering all four plant species, in different doses and dates of evaluation, 72 dicamba-haloxyfop interactions were evaluated, in which 50 were considered additives. However, the possibility of antagonism (9 interactions) or even synergy (13 interactions) cannot be ruled out, subjected to the influence of the herbicide dose, plant species and moment of evaluation.

Biología y morfología externa de los estadios inmaduros de Spodoptera dolichos (Lepidoptera: Noctuidae)

Se describen la morfología externa y la biología de los estadios inmaduros de Spodoptera dolichos (Fabricius, 1974), (Lepidoptera: Noctuidae). Las larvas fueron colectadas en Ipomoea triloba L. (Convolvulaceae), lo cual constituye un nuevo registro de planta hospedera. Se ofrecen fotografías de los huevos, los siete estadios larvales y la pupa. Se describe e ilustra la morfología cefálica y la quetotaxia del primer estadio. Los resultados se comparan con los aspectos conocidos de otros estadios inmaduros de Spodoptera.

INTERAÇÃO E EFICÁCIA DE MISTURAS EM TANQUE DOS HERBICIDAS SAFLUFENACIL E GLYPHOSATE

O uso repetitivo do herbicida glyphosate e em elevadas doses tem selecionado biótipos de plantas daninhas resistentes, além de favorecer à seleção de plantas tolerantes ao mesmo. A solução mais comum nestes casos é a inclusão de herbicidas alternativos no sistema de produção, aplicados de forma isolada ou misturados em tanque. Desta forma, este trabalho foi desenvolvido com o objetivo de avaliar a eficácia e a interação de misturas de saflufenacil com o herbicida glyphosate para controle de plantas daninhas. Foram desenvolvidos dois experimentos independentes, avaliando-se duas espécies de plantas daninhas, uma monocotiledônea (capim-amargoso - Digitaria insularis) e uma dicotiledônea (corda-de-viola - Ipomoea triloba). Os tratamentos constaram de esquema fatorial 4x4, com quatro doses do herbicida glyphosate (0, 360, 720 e 1.080 g e.a. ha-1) e quatro doses do herbicida saflufenacil (0, 21, 42 e 63 g ha-1). Em ambos os trabalhos se adotou delineamento experimental de blocos ao acaso e cinco repetições. Dentre as combinações testadas, a mistura foi considerada aditiva para o capim-amargoso e para a corda-de-viola. Estas misturas foram consideradas importantes ferramentas para controle de plantas daninhas resistentes e tolerantes nos sistemas de produção, sendo o saflufenacil uma excelente molécula a ser utilizada em acompanhamento ao herbicida glyphosate.

MANAGEMENTS MORNING GLORY IN COMPETITION WITH MAIZE IN ORGANIC SYSTEM

One of the biggest obstacles to organic maize cultivation is weed management. The aim of this work was to evaluate the mowing and weeding in the control of densities of Ipomoea triloba (morning glory) in competition with maize. The experiment was installed in a completely randomized design, with four replications, in the factorial scheme 3 x 3 + 1. The first factor was constituted by three densities of the species I. triloba and the second by three weed management. The additional treatment consisted in the cultivation of maize free from I. triloba interference. The mowing done in the V4 stage of maize did not minimize the competition of I. triloba. Weeding was more efficient for control at higher densities. The I. tribola showed regrowth and despite accumulating reduced dry mass, it was more efficient in the uptake of N, P, K, and Mg in relation to the uncropped plants.

Effect of Sugar and Alcohol Industry Byproducts on Pre-Emergence Herbicide Efficacy

The present study evaluate the effects of vinasse and filter cake on the efficacy of indaziflam, saflufenacil, and sulfentrazone for the control of morning glory (Ipomoea triloba L.) and crabgrass (Digitaria horizontalis Wiild), as well as the effects of these byproducts on the emergence of these weeds. The experiments were established in a greenhouse with a completely randomized design and four replications at the Agricultural Science Center, Sao Paulo, Brazil, between May 2017 and May 2018. In the first assay, four herbicide doses: indaziflam (0, 37.5, 75, and 150 g ai ha-1), saflufenacil (0, 42, 84, and 168 g a.i ha-1), and sulfentrazone (0, 300, 600, and 1200 g ai ha-1) were applied for pre-emergent weeds in three soil covers (without byproduct, with vinasse, and with filter cake).In the second assay, seven treatments were evaluated, comparing the effects of the different vinasse and filter cake doses, and absence of byproduct on the weeds emergence. When the doses required for 80% effective control were considered, the results showed that for indaziflam, the filter cake negatively affected crabgrass control. In contrast, vinasse had a positive effect on morning glory control by saflufenacil. For sulfentrazone, the filter cake had a negative effect, requiring twice the dose used on the treatment without byproduct for effective morning glory control. Relative to assay 2, the vinasse addition affected the emergence of morning glory but not of crabgrass; however, the filter cake increased the weed biomass accumulation. Vinasse and filter cake byproducts can negatively or positively affect the performance of pre-emergence herbicides, according to the active ingredient used. However, these effects occur at doses below those recommended for the herbicides. Byproducts can affect the emergence and the weed biomass accumulation.