Glucosinolates are sulfur-containing defense compounds produced by brassica plants. Brassica napus (canola) is an important oilseed crop because a low-glucosinolate variety has been developed. Brassica juncea is more stress tolerant, but has not been developed as a crop due to its high levels of glucosinolates. In a “transport engineering” approach, Nour-Eldin et al. identified glucosinolate […]
Plant reproduction is particularly sensitive to heat stress, so rising temperature is a major threat to food security. Zhang et al. surveyed the transcriptional responses to heat stress (3 h at 37º) in Arabidopsis and identified large differences between vegetative and reproductive tissue responses to heat. In reproductive tissue, heat-responsive genes include those participating in […]
Photosynthesis in plants involves two photosystems acting in series, Photosystem I (PSI) and PSII. Each photosystem is a massive complex consisting of numerous proteins and pigments. The photosystems are efficient at light harvesting but also sensitive to high-light induced photooxidative damage. Photosynthetic organisms have several ways to protect against high-light damage, one of which is […]
The final step in the synthesis of chlorophyll is the joining of chlorophyllide, (a tetrapyrrole with planar structure similar to heme) to a linear lipid (a product of the terpenoid pathway) that provides an attachment point for the resulting chlorophyll to pigment-binding proteins of the light-harvesting complexes. LIL3 (Light-harvesting-Like) is a membrane-spanning protein that was […]
Hybrid vigor is a well-known but still poorly understood phenomenon in which the F1 hybrid progeny of a cross often show enhanced growth as compared to either parent. True-breeding lines that retain this enhanced growth, known as hybrid mimics, have been developed and are important tools for understanding hybrid vigor. Wang et al. characterized several […]
Flooding “drowns” plants by depriving them of oxygen, leading to hypoxia and ultimately death. Ethylene-responsive transcription factors (ERFs) have been identified that induce expression of genes to support anaerobic metabolism and are critical for hypoxia survival. ERFs are selectively destabilized in normal oxygen environment (normoxia), through a turnover response known as the N-end rule pathway, […]
Trans-acting small interfering RNAs (tasiRNAs) are unique to plants. They are the products of TAS genes, but they function to regulate other genes (thus the name “trans-acting”). The production of tasiRNAs requires miRNAs, which bind to and ultimately lead to cleavage of the primary TAS transcript. TAS3 is the best studied TAS gene. Its production […]
Gene silencing by chromatin marks occurs in plants and animals, but there are often some differences in the details. Polycomb repressive complex 1 (PRC1) and PRC2 were first characterized in animals and shown to repress gene expression in part through histone modification; PRC1 has histone H2A E3 ubiquitin ligase activity, and PRC2 has histone H3 […]
It is well established that plastids are derived from the primary endosymbiosis of an ancient cyanobacterium into a eukaryotic host cell, but this understanding does not explain all of the evidence, nor does it explain how the nascent endosymbiont evaded the host cell’s defense mechanisms. Recently, the ménage-à-trois hypothesis (MATH) was proposed. According to MATH, […]