Key message

Tomato pollen grains have the capacity for ethylene production, possessing specific components of the ethylene-biosynthesis and -signaling pathways, being affected/responsive to high-temperature conditions.

Abstract

Exposure of plants to heat stress (HS) conditions reduces crop yield and quality, mainly due to sensitivity of pollen grains. Recently, it was demonstrated that ethylene, a gaseous plant hormone, plays a significant role in tomato pollen heat-tolerance. It is not clear, however, whether, or to what extent, pollen grains are dependent on the capacity of the surrounding anther tissues for ethylene synthesis and signaling, or can synthesize this hormone and possess an active signaling pathway. The aim of this work was (1) to investigate if isolated, maturing and mature, tomato pollen grains have the capacity for ethylene production, (2) to find out whether pollen grains possess an active ethylene-biosynthesis and -signaling pathway and characterize the respective tomato pollen components at the transcript level, (3) to look into the effect of short-term HS conditions. Results from accumulation studies showed that pollen, anthers, and flowers produced ethylene and HS affected differentially ethylene production by (rehydrated) mature pollen, compared to anthers and flowers, causing elevated ethylene levels. Furthermore, several ethylene synthesis genes were expressed, with SlACS3 and SlACS11 standing out as highly HS-induced genes of the pollen ethylene biosynthesis pathway. Specific components of the ethylene-signaling pathway as well as several ethylene-responsive factors were expressed in pollen, with SlETR3 (ethylene receptor; named also NR, for never ripe) and SlCTR2 (constitutive triple response2) being HS responsive. This work shows that tomato pollen grains have the capacity for ethylene production, possessing active ethylene-biosynthesis and -signaling pathways, highlighting specific pollen components that serve as a valuable resource for future research on the role of ethylene in pollen thermotolerance.

中文翻译：

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番茄（Solanum lycopersicum）花粉粒中的乙烯产生和信号传递对热胁迫条件有响应。

关键信息

番茄花粉粒具有生产乙烯的能力，具有乙烯生物合成和信号传导途径的特定成分，受到高温条件的影响/对高温条件有反应。

抽象

植物暴露于热胁迫（HS）条件下会降低作物的产量和品质，这主要是由于花粉粒的敏感性所致。最近，已证明乙烯，一种气态植物激素，在番茄花粉耐热性中起重要作用。然而，尚不清楚花粉粒是否或在何种程度上取决于周围的花药组织进行乙烯合成和信号传导的能力，或者是否可以合成这种激素并具有活跃的信号传导途径。这项工作的目的是（1）研究分离的，成熟的和成熟的番茄花粉粒是否具有生产乙烯的能力，（2）查明花粉粒是否具有活跃的乙烯生物合成和信号传导途径并表征其特征。转录水平上的各个番茄花粉成分，（3）研究短期HS条件的影响。积累研究的结果表明，与花药和花朵相比，花粉，花药和花朵产生的乙烯和HS对（再水化的）成熟花粉的乙烯产量产生不同的影响，从而导致乙烯含量升高。此外，表达了几个乙烯合成基因，SlACS3和SlACS11是高度HS诱导的花粉乙烯生物合成途径的基因。乙烯信号传导途径的特定成分以及一些乙烯响应因子在花粉中表达，其中SlETR3（乙烯受体；永不成熟，也称为NR）和SlCTR2（本构三联反应2）对HS响应。这项工作表明，番茄花粉粒具有生产乙烯的能力，具有活跃的乙烯生物合成和信号传导途径，突出了特定的花粉成分，为将来研究乙烯在花粉耐热性中的作用提供了宝贵的资源。