Bielsa F J, Grimplet J, Irisarri P, Miranda C, Errea P, Pina A
Centro de Investigación y Tecnología Agroalimentaria de Aragón (CITA), Departamento de Ciencia Vegetal, Avenida Montañana 930, Zaragoza, 50059, Spain.
Instituto Agroalimentario de Aragón-IA2, CITA-Universidad de Zaragoza, Zaragoza, 50013, Spain.
BMC Plant Biol. 2025 Apr 12;25(1):467. doi: 10.1186/s12870-025-06445-6.
Enzymatic browning (EB) endangers the adaptation of apple fruit cultivars to new markets, affecting organoleptic properties and producing economic losses. Polyphenol oxidases and polyphenol compounds play a key role in EB development in apple. However, the regulation of apple response to EB remains to be uncovered. In this study, three apple cultivars with different EB phenotypes ranging from low to high browning in apple pulp were used to study transcriptomic changes over time after fresh cutting (0, 30 and 60 min). This study allowed the identification of 1448 differentially expressed genes (DEGs), revealing both shared and genotype-specific responses, particularly in the affected metabolic pathways associated with EB. At 60 min (T60 vsT0), 77 DEGs were shared by all genotypes, suggesting a conserved regulatory network. This network included genes encoding for protein families such as calcium-binding proteins, heat-shock proteins, redox-responsive transcription factors, WRKY family transcription factors, zinc finger family proteins and disease resistance proteins among others. A co-expressed gene cluster, identified through Weighed Gene Co-Expression Network Analysis (WGCNA), was found to correlate with EB and included 323 genes enriched in several biological terms according to Gene Ontology analysis. Moreover, a more detailed analysis of identified WGCNA gene cluster regulatory sequences allowed the detection of cis-regulatory elements belonging to CAMTA, WRKY and WUSCHEL transcription factor families. The identification of these sequences alongside with an abundant and diverse amount of overexpressed transcription factors from various families (WRKY, ERF, GRAS, GATA, etc.) point out to a highly regulated stress-response that is strictly connected to innate plant immunity. These findings provide valuable insights into the molecular mechanism involved in apple fresh-cut browning and offer new potential targets for EB regulation.
酶促褐变（EB）危及苹果果实品种对新市场的适应性，影响感官特性并造成经济损失。多酚氧化酶和多酚化合物在苹果的酶促褐变过程中起关键作用。然而，苹果对酶促褐变反应的调控机制仍有待揭示。在本研究中，选用了三个苹果果肉酶促褐变表型从低到高的品种，研究鲜切后不同时间（0、30和60分钟）的转录组变化。本研究鉴定出1448个差异表达基因（DEG），揭示了共同的和基因型特异性的反应，特别是在与酶促褐变相关的受影响代谢途径中。在60分钟时（T60 与T0），所有基因型共有77个差异表达基因，表明存在一个保守的调控网络。该网络包括编码钙结合蛋白、热休克蛋白、氧化还原反应转录因子、WRKY家族转录因子、锌指家族蛋白和抗病蛋白等蛋白家族的基因。通过加权基因共表达网络分析（WGCNA）鉴定出一个共表达基因簇，发现其与酶促褐变相关，根据基因本体分析，该基因簇包含323个在多个生物学术语中富集的基因。此外，对鉴定出的WGCNA基因簇调控序列进行更详细的分析，发现了属于CAMTA、WRKY和WUSCHEL转录因子家族的顺式调控元件。这些序列的鉴定以及来自各个家族（WRKY、ERF、GRAS、GATA等）的大量且多样的过表达转录因子表明，存在一个高度调控的应激反应，该反应与植物先天免疫密切相关。这些发现为苹果鲜切褐变所涉及的分子机制提供了有价值的见解，并为酶促褐变调控提供了新的潜在靶点。
