蔬菜作物应答非生物逆境胁迫的分子生物学研究进展

Progresses in Research on Molecular Biology of Abiotic Stress Responses in Vegetable Crops

蔬菜作为重要的经济作物,近年来的种植面积、产量及需求都在不断增加。蔬菜作物在生长和发育过程中经常受到非生物逆境(包括干旱、盐、极端温度及重金属胁迫等)的侵害,影响其产量及品质。近十年来,国内外关于蔬菜应答非生物逆境胁迫的分子生物学研究领域取得了一定的进展。在应答干旱胁胁迫方面,DREB、WRKY、NAC、b HLH及b ZIP等转录因子受干旱信号诱导,调节下游抗旱基因的表达,从而提高蔬菜作物抗旱能力。同时,水分运输相关功能基因(PIP、TIP)、E3连接酶SIZ1及脱水蛋白DHN也被报道受干旱诱导,并通过调节水势、渗透势及ROS积累抵御干旱胁迫。在抵御盐胁迫方面,SOS途径至关重要。Sl SOS2能够通过调节Sl SOS1和Na+/H+逆向转运蛋白Le NHX2/4的表达维持离子平衡和调节植物器官中Na+的分配。蔬菜抗盐研究中NAC、ERF、MYB等转录因子响应盐胁迫并激活抗逆相关基因表达,从而提高蔬菜作物抗盐能力。此外蔬菜植物大量合成渗透调节物质是其抵御盐胁迫的常见方式。吡咯啉-5-羧酸合成酶Pv P5CS和tom PRO2、脯氨酸脱氢酶Boi Pro DH等在盐胁迫下能提高脯氨酸的含量;过表达甜菜碱醛脱氢酶Sl BADH能提高番茄中甜菜碱含量。在高温胁迫响应过程中,HSFs位于调控网络的核心位置,可调控包括HSPs在内的一系列抗逆基因的表达,番茄中热激转录因子Sl HSFs相互之间形成复合体调控下游Sl HSPs的表达而应答高温逆境。在低温胁迫中,CBFs/EREBs位于调控网络的核心位置,并受ICE1调控;LEA及HSPs蛋白在低温下能够防止细胞中蛋白质变性并维持细胞膜流动性。蔬菜应答重金属胁迫主要依靠体内隔离和体内外螯合机制。在蔬菜应答非生物逆境的过程中,ABA作为信号受体起到至关重要的作用。蔬菜中NAC、MYB、HSF等转录因子则受ABA信号诱导,应答非生物逆境,进而提高活性氧清除能力,合成更多抗逆物质,从而抵御非生物逆境的侵害。

As an important economic crop, acreage, yield and demand of vegetable have been increased in recent years. Vegetables are inescapably affected by abiotic stresses including drought, salt, extreme temperature, heavy metal. These stresses seriously affect yield and quality of vegetable crops. During the recent decade, the studies on vegetables against abiotic stress have made some progress. Studies about drought stress focused on transcription factors such as DREB, WRKY, NAC, b HLH and b ZIP in vegetables. These transcription factors were induced by drought stress and regulated the expressions of downstream genes to resist drought stress. Water transport genes（PIP, TIP）, E3 ligase SIZ1 and DHN were also reported to be drought induced, and they rebalanced water potential, osmotic potential and reduced the ROS accumulation. The SOS pathway is critical in resisting salt stress. SlSOS2 upregulated the expressions of SlSOS1 and Le NHX2/4, which could maintain ion homeostasis and regulate the distribution of Na＋ in plant organs under salt stress. To resist salt stress, NAC, ERF and MYB responded to salt stress and induced the expressions of tolerance-related genes. Furthermore, the synthesis of osmolyte is a common way to resist salt stress in vegetables. Pv P5 CS, tom PRO2 and Boi Pro DH improved the accumulation of proline, and Sl BADH synthesized betaine under salt stress condition. As for extreme temperatures, extremes of cold and heat are threats to the plant growth. In response to high temperature stress, HSFs are the core of the regulatory network and can regulate series of anti-stress genes; including HSPs. Sl HSFs formed a complex with each other to regulate the expressions of Sl HSPs to resist heat stress in tomato. CBFs/EREBs were the core factors of cold stress and regulated by ICE1. LEA and HSPs prevented protein denaturation and maintained cell membrane fluidity at low temperature. To resist heavy metal stress, vegetables mainly depend on isolation in vivo and chelation mechanism in vivo and in vitro. In response to abiotic stresses in vegetables, ABA plays a crucial role as a signaling receptor. NAC, MYB, HSF and other transcription factors were induced by ABA signaling and responded to abiotic stress. These transcription factors enhanced the scavenging capacity of reactive oxygen species and synthesize more anti adversity substances in vegetables to resist multiple abiotic stresses.