Occurrence and distribution of single or mixed infection of phytoplasma and spiroplasma causing corn stunting in Brazil

Abstract

Maize bushy stunt and corn stunt have emerged among the most important diseases of maize in Brazil. To evaluate the single or dual presence of the phytoplasma and spiroplasma associated with corn stunting diseases, maize samples were collected across several locations in four Brazilian states. Multiplex PCR was performed for simultaneous detection of the bacteria. Eighty-nine out of 100 samples were positive with percentage values of 40%, 35%, and 25% for phytoplasma, spiroplasma, and mixed infections, respectively. Temperature may be an important driver of the prevalence of these mollicutes as phytoplasma prevailed in areas with mild temperatures and spiroplasma prevailed in warmer areas. These results extend knowledge of factors associated with corn stunting diseases, such as the potential role of temperature shaping the composition of the regional plant pathogenic populations.

Incidence and effect on grain yield of the “monkey’s hand” disease in 29 maize genotypes

“…Sin embargo, este cultivo es afectado por diversos problemas fitosanitarios que disminuyen considerablemente su producción, entre los que destacan especialmente las enfermedades de origen fungoso (CIMMYT, 2005). En los últimos años, un grupo de fitopatógenos de la clase Mollicutes, entre los que se incluyen los espiroplasmas y fitoplasmas, originalmente considerados como un grupo secundario, han cobrado importancia en diversos cultivos, incluyendo el maíz (Galvão et al, 2020).…”

“…However, this crop is affected by diverse phytosanitary problems that considerably reduce its production, with fungal diseases being amongst the most important (CIMMYT, 2005). In recent years, a group of phytopathogens of the Mollicutes Class, including spiroplasms and phytoplasms, originally considered as a secondary group, have become increasingly important in diverse crops, including maize (Galvão et al, 2020).…”

Assessing the Functionality of RNA Interference (RNAi) in the Phloem-feeding Maize pestDalbulus maidis

“…At least seven vector-borne diseases are known in maize, five of which are viral and two bacterial (Carloni et al, 2013;Hammond & Bedendo, 2005;Liu & Wang, 2018;Meyer & Pataky, 2010;Orlovskis et al, 2017;Zhang et al, 2011). Dalbulus maidis is the insect vector responsible for transmitting three of the most important maize disease agents, namely Maize rayado fino virus (MRFV), Maize bushy stunt phytoplasma, and Spiroplasma kunkelii (CSS), which it can acquire and transmit together or individually (Galvão et al, 2020;Mlotshwa et al, 2020;Sabato et al, 2020). Pathogens vectored by D. maidis are transmitted in a persistent, propagative manner, and as such D. maidis remains a vector throughout its life cycle, which facilitates disease spread across maize fields (Canale et al, 2018;Luft Albarracin et al, 2009;Ramos et al, 2020).…”

Efeito do estádio de desenvolvimento da planta e densidade populacional do inseto vetor, >i<Dalbulus maidis>/i< (DeLong & Wolcott) (Hemiptera: Cicadellidae), sobre a transmissão e danos do fitoplasma do milho

“…As características bioecológicas da cigarrinha-do-milho supracitadas influenciam diretamente a disseminação dos molicutes, seja em escala local ou regional. Esses patógenos têm aumentado em incidência e distribuição no Brasil, sendo que a distribuição está relacionada com temperatura do ambiente (Galvão et al 2020). Em geral, são favorecidos por temperaturas elevadas, mas respondem de maneira distinta mediante variações dessa condição ambiental, com implicações na eficiência de transmissão pela cigarrinha (Moya-Raygoza and Nault 1998;Sabato et al 2020), e na severidade da doença (Sabato et al 2020).…”

“…Como a cigarrinha-do-milho se apresenta como a única forma de disseminação dos molicutes, fatores que a favorecem podem implicar em mudanças na epidemiologia da doença (Moya-Raygoza and Nault 1998;). Atualmente, no Brasil, os enfezamentos são doenças emergentes com ocorrência frequente em várias regiões (Galvão et al 2020), mas originalmente possuíam o status de doença secundária e, em surtos esporádicos, registrava-se perdas (Oliveira et al 1998). O aumento da importância dos enfezamentos é explicado pela mudança no sistema de produção do milho (Bedendo and Lopes 2019).…”