Latin America is the center of domestication and diversity of maize, the second most cultivated crop worldwide. In this region, maize landraces are fundamental for food security, livelihoods, and culture. Nevertheless, genetic erosion (i.e., the loss of genetic diversity and variation in a crop) threatens the continued cultivation and in situ conservation of landrace diversity that is crucial to climate change adaptation and diverse uses of maize. We provide an overview of maize diversity in Latin America before discussing factors associated with persistence of large in situ maize diversity, causes for maize landrace abandonment by farmers, and strategies to enhance the cultivation of landraces. Among other factors, maize diversity is linked with: (1) small-holder farming, (2) the production of traditional food products, (3) traditional cropping systems, (4) cultivation in marginal areas, and (5) retention of control over the production system by the farmers. On the other hand, genetic erosion is associated with substitution of landraces with hybrid varieties or cash crops, and partial (off-farm labor) or complete migration to urban areas. Continued cultivation, and therefore on-farm conservation of genetic diversity held in maize landraces, can be encouraged by creating or strengthening market opportunities that make the cultivation of landraces and open pollinated varieties (OPVs) more profitable for farmers, supporting breeding programs that prioritize improvement of landraces and their special traits, and increasing the access to quality germplasm of landraces and landrace-derived OPVs.
BÁRBARA FRANÇA DANTAS 2 , CARLOS ALBERTO ARAGÃO 3 , JOÃO PESSOA ARAÚJO-JUNIOR 4 , JOÃO DOMINGOS RODRIGUES 5 , CLÁUDIO CAVARIANI 6 , JOÃO NAKAGAWA 6RESUMO -Durante a germinação das sementes, os carboidratos de reserva são degradados pela atividade de α-amilase. A identificação de mRNA é uma ferramenta fundamental para a definição da cinética de síntese de a-amilase. Objetivou-se padronizar a metodologia do RT-PCR para identificar o mRNA do gene de α-amilase em sementes de milho. Após três dias de germinação das cultivares Saracura-BRS 4154 e CATI-AL34, extraiu-se o RNA total pelo método do tiocianato de guanidina-fenol-clorofórmio, com algumas modificações. A partir do RNA total extraído foi obtido cDNA com utilização de "random primers". A amplificação por PCR de uma porção do gene da α-amilase foi realizada com os "primers": "sense" -CGACATCGACCACCTCAAC; "antisense" -TTGACCAGCTCCTGCCTGTC; gelatina; DMSO e 1,25 unidades de Taq DNA polimerase por reação e completados com água tratada com DEPC. Os ciclos para a amplificação foram 94 o C durante 4 minutos, seguidos por 34 ciclos de 94 o C durante 1 minuto, 42 o C durante 1 minuto e 72 o C durante 1,5 minutos e, finalmente, 72 o C por 5 minutos. O produto do RT-PCR apresentou uma banda de 249 pares de base (pb) bem definida, para as duas cultivares estudadas, não ocorrendo bandas inespecíficas. A técnica do RT-PCR mostrou ser uma metodologia eficiente para a identificação da expressão de α-amilase durante a germinação das sementes e pode ser usado para estudo qualitativo e quantitativo da cinética de síntese dessa enzima em experimentos de germinação.Termos para indexação: Zea mays, sementes, α-amilase, RT-PCR. RT-PCR PATTERNING FOR α-AMYLASE MESSENGER RNA IDENTIFICATION IN GERMINATING MAIZE SEEDSABSTRACT -During germination the seed reserve carbohydrates are degraded by α-amylase activity. The identification of mRNA is a very important tool for definition of α-amylase synthesis kinetics. This study aimed to adapt a PT-PCR methodology for α-identification of amylase mRNA in germinating maize seeds. After three days germination of Saracura BRS4154 and CATI AL34 maize cultivars, the total RNA was isolated by the guanidinium thiocyanate-phenol-chloroform extraction method, with some modifications. The cDNA was obtained from the total RNA, using random primers. The α-amylase gene PCR amplification was carried out with cDNA, primers (sense -CGACATCGACCACCTCAAC; antisense -TTGACCAGCTCCTGCCTGTC); gelatina; DMSO and 1,25 units of Taq DNA polimerase per reaction and complete with DEPC water. The amplification cycles were 94 o C/4 minutes, 34 cycles of 94 o C /1 minute, 42 o C/1 minute
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.