Briones-Moreno Asier, Hernández-García Jorge, Vargas-Chávez Carlos, Romero-Campero Francisco J, Romero José M, Valverde Federico, Blázquez Miguel A
Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas - Universidad Politécnica de ValenciaValencia, Spain.
Institute for Integrative Systems Biology (I2SysBio), University of ValenciaValencia, Spain.
Front Plant Sci. 2017 Apr 25;8:626. doi: 10.3389/fpls.2017.00626. eCollection 2017.
DELLA proteins are transcriptional regulators present in all land plants which have been shown to modulate the activity of over 100 transcription factors in Arabidopsis, involved in multiple physiological and developmental processes. It has been proposed that DELLAs transduce environmental information to pre-wired transcriptional circuits because their stability is regulated by gibberellins (GAs), whose homeostasis largely depends on environmental signals. The ability of GAs to promote DELLA degradation coincides with the origin of vascular plants, but the presence of DELLAs in other land plants poses at least two questions: what regulatory properties have DELLAs provided to the behavior of transcriptional networks in land plants, and how has the recruitment of DELLAs by GA signaling affected this regulation. To address these issues, we have constructed gene co-expression networks of four different organisms within the green lineage with different properties regarding DELLAs: and (both with GA-regulated DELLA proteins), (with GA-independent DELLA proteins) and (a green alga without DELLA), and we have examined the relative evolution of the subnetworks containing the potential DELLA-dependent transcriptomes. Network analysis indicates a relative increase in parameters associated with the degree of interconnectivity in the DELLA-associated subnetworks of land plants, with a stronger effect in species with GA-regulated DELLA proteins. These results suggest that DELLAs may have played a role in the coordination of multiple transcriptional programs along evolution, and the function of DELLAs as regulatory 'hubs' became further consolidated after their recruitment by GA signaling in higher plants.
DELLA蛋白是所有陆地植物中存在的转录调节因子，已证明其可调节拟南芥中100多种转录因子的活性，参与多种生理和发育过程。有人提出，DELLA蛋白将环境信息传递到预先设定的转录回路，因为它们的稳定性受赤霉素（GA）调节，而赤霉素的稳态很大程度上取决于环境信号。GA促进DELLA降解的能力与维管植物的起源一致，但其他陆地植物中DELLA蛋白的存在至少提出了两个问题：DELLA蛋白为陆地植物转录网络的行为提供了哪些调节特性，以及GA信号对DELLA蛋白的招募如何影响这种调节。为了解决这些问题，我们构建了绿色谱系中四种不同生物体的基因共表达网络，它们在DELLA蛋白方面具有不同特性：[具体物种1]和[具体物种2]（两者都有GA调节的DELLA蛋白）、[具体物种3]（有GA独立的DELLA蛋白）和[具体物种4]（一种没有DELLA的绿藻），并且我们研究了包含潜在DELLA依赖转录组的子网络的相对进化。网络分析表明，陆地植物中与DELLA相关的子网络中，与互连程度相关的参数相对增加，在具有GA调节的DELLA蛋白的物种中影响更强。这些结果表明，DELLA蛋白可能在进化过程中多个转录程序的协调中发挥了作用，并且在高等植物中被GA信号招募后，DELLA蛋白作为调节“枢纽”的功能得到了进一步巩固。
