Acquiring high-quality RNA in sufficient amounts is crucial in plant molecular biology and genetic studies. Several methods for RNA extraction from plants are available in the literature, mainly due to the great biochemical diversity present in each species and tissue, which can complicate or prevent the extraction. Psidium guajava (Myrtaceae family) is a perennial fruit tree of medicinal and economic value; nevertheless, only a few molecular studies are available for the species. One reason is the difficulty in obtaining RNA due to the content of the samples, which are rich in polyphenols, polysaccharides, and secondary metabolites. Furthermore, there are few studies available for the isolation of RNA from guava or Psidium samples, which hampers advances in the study of the genus. Here, quality and yields of RNA isolates were compared using six extraction protocols: two protocols based on the application of cetyltrimethylammonium bromide (CTAB) lysis buffer, one protocol which uses the TRIzol reagent, one which applies guanidine thiocyanate lysis buffer followed by organic phase extraction, and two commercial kits (PureLink RNA Mini Kit and RNeasy Plant Mini Kit). The CTAB-based method provided the highest RNA yields and quality for five different tissues (flower bud, immature leaf, young leaf, mature leaf, and root), genotypes, and stress conditions. For the most efficient protocol, the average yield of RNA from guava leaves was 203.06 μg/g of tissue, and the A260/A280 and A260/A230 ratios were 2.1 and 2.2, respectively. RT-qPCR analysis demonstrated that the purity of the samples was sufficient for molecular biology experiments. CTAB-based methods for RNA isolation were found to be the most efficient, providing the highest RNA yields and quality for tissues from P. guajava. Additionally, they were compatible for downstream RNA-based applications, besides being simple and cost-effective.

中文翻译：

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从 Psidium guajava L. 组织中分离高质量 RNA 的有效方法。

获得足量的高质量 RNA 在植物分子生物学和遗传研究中至关重要。文献中提供了几种从植物中提取 RNA 的方法，主要是由于每个物种和组织中存在巨大的生化多样性，这会使提取复杂化或阻碍提取。番石榴（桃金娘科）是多年生果树，具有药用和经济价值；然而，只有少数分子研究可用于该物种。原因之一是由于样品中含有丰富的多酚、多糖和次级代谢物，因此难以获得 RNA。此外，很少有研究可用于从番石榴或 Psidium 样品中分离 RNA，这阻碍了该属研究的进展。这里，使用六种提取方案比较 RNA 分离物的质量和产量：两种方案基于应用十六烷基三甲基溴化铵 (CTAB) 裂解缓冲液，一种方案使用 TRIzol 试剂，一种方案使用硫氰酸胍裂解缓冲液，然后有机相提取，以及两个商业试剂盒（PureLink RNA Mini Kit 和 RNeasy Plant Mini Kit）。基于 CTAB 的方法为五种不同的组织（花芽、未成熟叶、幼叶、成熟叶和根）、基因型和胁迫条件提供了最高的 RNA 产量和质量。对于最有效的方案，番石榴叶的平均 RNA 产量为 203.06 μg/g 组织，A260/A280 和 A260/A230 比率分别为 2.1 和 2.2。RT-qPCR 分析表明样品的纯度足以进行分子生物学实验。发现基于 CTAB 的 RNA 分离方法是最有效的，为来自 P. guajava 的组织提供最高的 RNA 产量和质量。此外，除了简单且经济高效之外，它们还兼容下游基于 RNA 的应用。