A Functional Antagonistic Relationship between Auxin and Mitochondrial Retrograde Signaling Regulates Alternative Oxidase1a Expression in Arabidopsis.

The perception and integration of stress stimuli with that of mitochondrion function are important during periods of perturbed cellular homeostasis. In a continuous effort to delineate these mitochondrial/stress-interacting networks, forward genetic screens using the mitochondrial stress response marker alternative oxidase 1a (AOX1a) provide a useful molecular tool to identify and characterize regulators of mitochondrial stress signaling (referred to as regulators of alternative oxidase 1a [RAOs] components). In this study, we reveal that mutations in genes coding for proteins associated with auxin transport and distribution resulted in a greater induction of AOX1a in terms of magnitude and longevity.

OsGLU3, a putative membrane-bound endo-1,4-beta-glucanase, is required for root cell elongation and division in rice (Oryza sativa L.).

Plant roots move through the soil by elongation. This is vital to their ability to anchor the plant and acquire water and minerals from the soil. In order to identify new genes involved in root elongation in rice, we screened an ethyl methane sulfonate (EMS)-mutagenized rice library, and isolated a short root mutant, Osglu3-1.

Ammonium affects cell viability to inhibit root growth in Arabidopsis.

Ammonium (NH₄⁺) is an important form of nitrogen nutrient for most plants, yet is also a stressor for many of them. However, the primary events of NH₄⁺ toxicity at the cellular level are still unclear. Here, we showed that NH₄⁺ toxicity can induce the root cell death in a temporal pattern which primarily occurs in the cells of root maturation and elongation zones, and then spreads to the cells in the meristem and root cap.

[The structure and phosphorus or potassium deficiency induced expression of a calmodulin-like protein gene in Arabidopsis].

According to our previous microarray analysis, we found a putative calmodulin gene related to Pi deficiency and designated AtPsiCaM (Arabidopsis Pi-starvation-induced CaM). Results of structural analysis indicate that AtPsiCaM has three conserved EF-hands motif and belongs to calmodulin-like proteins family (Figs. 1-3).

Comparative mapping of QTLs for Al tolerance in rice and identification of positional Al-induced genes.

Aluminum (Al) toxicity is the major factor limiting crop productivity in acid soils. In this study, a recombinant inbreed line (RIL) population derived from a cross between an Al sensitive lowland indica rice variety IR1552 and an Al tolerant upland japonica rice variety Azucena, was used for mapping quantitative trait loci (QTLs) for Al tolerance. Three QTLs for relative root length (RRL) were detected on chromosome 1, 9, 12, respectively, and 1 QTL for root length under Al stress is identical on chromosome 1 after one week and two weeks stress.

Seminal, adventitious and lateral root growth and physiological responses in rice to upland conditions.

Understanding the growth and physiological responses of rice to upland conditions would be helpful for designing treatments to improve the tolerance of rice under a rainfed system. The objective of this study was to investigate the initiation,elongation and membrane stability of seminal, lateral and adventitious roots of upland rice after 9-d upland condition treatment. Compared with control roots under waterlogged conditions, upland water deficiency conditions favor seminal and lateral root growth over adventitious root growth by accelerating seminal root elongation, promoting lateral root initiation and elongation, and reducing the elongation and number of adventitious roots.