The domestication of crops was a significant event in human history, which led to the emergence and prosperity of agricultural civilization. Maize is an important global food crop, and its domestication origin has long attracted the attention of both the biological and historical communities. The mainstream view in the past was that modern maize originated from the parviglumis type of teosinte. Recently, Yan Jianbing and his collaborators systematically collected and sorted various types of wild and cultivated maize resources, and comprehensively applied genomics, population genetics, and quantitative genetics methods, along with the use of archaeological findings. They found that modern maize also has the gene introgression of the mexicana type of teosinte, which has influenced many agronomic traits. A new model for the origin of modern maize has been proposed based on these findings.

Auxin plays an important role in plant growth and development and its signal transduction has always been the focus of attention in the field of plant biology. AUXIN BINDING PROTEIN 1 (ABP1)-TRANSMEMBRANE KINASE (TMK) molecular module is involved in the extracellular auxin perception. In recent years, ABP1 has been controversial as an auxin receptor. Recently, Tongda Xu’s team and Zhenbiao Yang’s team from Fujian Agriculture and Forestry University identified ABP1-LIKE PROTEIN (ABL) as the auxin binding proteins involved in the extracellular auxin perception. Different from traditional functional redundancy, ABL and ABP1 achieve functional compensation effect through protein structure similarity, and then form complex with TMK at the plasma membrane, acting as co-receptors of apoplastic auxin to mediate auxin driven rapid response. This study deeply dissects the mechanism of extracellular auxin sensing, which is a breakthrough in the field of auxin signaling transduction.

Plants can coordinate the growth direction of their various organs upon the gravity stimulus. In the process of plant gravitropism, gravity sensing and gravity signal transduction have always been the focus of attention in the field of plants. The classical “starch-statolith” hypothesis proposes that plants sense gravity through the sedimentation of amyloplasts that contain starch granules. In addition, previous studies have shown that LAZY proteins regulate plant gravitropism by mediating the asymmetric distribution of auxin. However, the molecular mechanism underlying how sedimentation of amyloplasts triggers gravity signal transduction and its coordination with LAZY proteins remains unclear. Recently, Professor Haodong Chen’s team from Tsinghua University reveals that gravistimulation induces the phosphorylation of LAZY proteins via MKK5-MPK3 kinase pathway in Arabidopsis, which modulates the phosphorylation of LAZY proteins. The phosphorylated LAZY proteins can enhance their interaction with the TOC proteins on the surface of amyloplasts, leading to the enrichment of LAZY proteins on the surface of amyloplasts and the polarity relocation on the new bottom of plasma membrane. This study illustrates the molecular mechanism underlying gravity signal transduction in plants and establishes the molecular connection between gravity sensing and LAZY mediated auxin asymmetric distribution, which is a major breakthrough in the field of plant gravitropism.

Aphids and the viruses transmitted by them cause some of the most devastating plant diseases across the globe. Once infected by aphids, plants can produce and release volatile organic compounds (VOCs), which are transmitted through air and elicit defense in neighboring plants (airborne defense, AD). However, the mechanisms underlying AD remained largely elusive. Dr. Yule Liu’s group at Tsinghua University, China, recently reports a new study and they identify a new signaling circuit, comprising methyl-salicylate (MeSA), salicylic-acid (SA)-binding protein-2 (SABP2), a transcription factor NAC2 and SA-carboxylmethyltransferase-1 (SAMT1) converting SA to MeSA, that mediate interplant communication and airborne defense against aphids and viruses. Furthermore, some virus-encoded virulence proteins could interact with NAC2 transcription factor to reduce the nuclear localization and promotes the degradation of NAC2, thereby suppressing the interplant AD and promoting viral transmission. This comprehensive study provides new mechanistic insights into airborne defense of plants and unravels an amazing aphid/virus co-evolutionary mutualism. It also sets the foundation for new approaches of using AD to control aphid and virus diseases in agriculturally-important plants.