Brassinosteroids (
Many plants require prolonged exposure to cold to acquire the competence to flower. The process by which cold exposure results in competence is known as vernalization. In
- NSF-PAR ID:
- 10051231
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- The Plant Journal
- Volume:
- 93
- Issue:
- 5
- ISSN:
- 0960-7412
- Page Range / eLocation ID:
- p. 871-882
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract BRs ) are essential plant growth‐promoting hormones involved in many processes throughout plant development, from seed germination to flowering time. SinceBRs do not undergo long‐distance transport, cell‐ and tissue‐specific regulation of hormone levels involves both biosynthesis and inactivation. To date, tenBR ‐inactivating enzymes, with at least five distinct biochemical activities, have been experimentally identified in the model plantArabidopsis thaliana . Epigenetic interactions betweenT‐DNA insertion alleles and genetic linkage have hindered analysis of higher‐order null mutants in these genes. A previous study demonstrated that thebas1‐2 sob7‐1 ben1‐1 triple‐null mutant could not be characterized due to epigenetic interactions between the exonicT‐DNA insertions inbas1‐2 andsob7‐1, causing the intronicT‐DNA insertion ofben1‐1 to revert to a partial loss‐of‐function allele. We usedCRISPR‐Cas9 genome editing to avoid this problem and generated thebas1‐2 sob7‐1 ben1‐3 triple‐null mutant. This triple‐null mutant resulted in an additive seedling long‐hypocotyl phenotype. We also uncovered a role forBEN1 BR ‐inactivation in seedling cotyledon petiole elongation that was not observed in the singleben1‐2 null mutant but only in the absence of bothBAS1 SOB7 BEN1 BAS1 SOB7 BAS1 BEN1 ,SOB7 -
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Abstract Plant development requires communication on many levels, including between cells and between organelles within a cell. For example, mitochondria and plastids have been proposed to be sensors of environmental stress and to coordinate their responses. Here we present evidence for communication between mitochondria and chloroplasts during leaf and root development, based on genetic and physical interactions between three
M echanosensitive channel ofS mall conductance‐L ike (MSL ) proteins fromArabidopsis thaliana .MSL proteins areArabidopsis homologs of the bacterialM echanos ensitivec hannel ofS mall conductance (MscS), which relieves cellular osmotic pressure to protect against lysis during hypoosmotic shock.MSL 1 localizes to the inner mitochondrial membrane, whileMSL 2 andMSL 3 localize to the inner plastid membrane and are required to maintain plastid osmotic homeostasis during normal growth and development. In this study, we characterized the phenotypic effect of a genetic lesion inMSL 1msl2 msl3 mutant backgrounds.msl1 single mutants appear wild type for all phenotypes examined. The characteristic leaf rumpling inmsl2 msl3 double mutants was exacerbated in themsl1 msl2 msl3 triple mutant. However, the introduction of themsl1 lesion into themsl2 msl3 mutant background suppressed othermsl2 msl3 mutant phenotypes, including ectopic callus formation, accumulation of superoxide and hydrogen peroxide in the shoot apical meristem, decreased root length, and reduced number of lateral roots. All these phenotypes could be recovered by molecular complementation with a transgene containing a wild type version ofMSL 1MSL 1 interacted with itself, but not withMSL 2 orMSL 3. These results establish that the abnormalities observed inmsl2 msl3 double mutants is partially dependent on the presence of functionalMSL 1 and suggest a possible role for communication between plastid and mitochondria in seedling development. -
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Abstract Flowering time and water‐use efficiency (
WUE ) are two ecological traits that are important for plant drought response. To understand the evolutionary significance of natural genetic variation in flowering time,WUE , andWUE plasticity to drought inArabidopsis thaliana , we addressed the following questions: (1) How are ecophysiological traits genetically correlated within and between different soil moisture environments? (2) Does terminal drought select for early flowering and drought escape? (3) IsWUE plasticity to drought adaptive and/or costly? We measured a suite of ecophysiological and reproductive traits on 234 spring flowering accessions ofA. thaliana grown in well‐watered and season‐ending soil drying treatments, and quantified patterns of genetic variation, correlation, and selection within each treatment.WUE and flowering time were consistently positively genetically correlated.WUE was correlated withWUE plasticity, but the direction changed between treatments. Selection generally favored early flowering and lowWUE , with drought favoring earlier flowering significantly more than well‐watered conditions. Selection for lowerWUE was marginally stronger under drought. There were no net fitness costs ofWUE plasticity.WUE plasticity (per se) was globally neutral, but locally favored under drought. Strong genetic correlation betweenWUE and flowering time may facilitate the evolution of drought escape, or constrain independent evolution of these traits. Terminal drought favored drought escape in these spring flowering accessions ofA. thaliana .WUE plasticity may be favored over completely fixed development in environments with periodic drought. -
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Summary To clarify the molecular bases of flowering time evolution in crop domestication, here we investigate the evolutionary fates of a set of four recently duplicated genes in soybean:
FT 2aFT 2bFT 2cFT 2dFLOWERING LOCUS TFT FT 2aFT 2bFT 2cFT 2dFT 2bFT 2dG. max andG. soja , the evolution ofFT 2cG. max lineage specific event. TheFT 2cFT 2c -
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Premise Light is critical in the ability of plants to accumulate chlorophyll. When exposed to far‐red (
FR ) light and then grown in white light in the absence of sucrose, wild‐type seedlings fail to green in a response known as theFR block of greening (BOG ). This response is controlled by phytochrome A through repression of protochlorophyllide reductase‐encoding (POR ) genes byFR light coupled with irreversible plastid damage. Sigma (SIG ) factors are nuclear‐encoded proteins that contribute to plant greening and plastid development through regulating gene transcription in chloroplasts and impacting retrograde signaling from the plastid to nucleus.SIG s are regulated by phytochromes, and the expression of someSIG factors is reduced in phytochrome mutant lines, includingphyA . Given the association of phyA with theFR BOG and its regulation ofSIG factors, we investigated the potential regulatory role ofSIG factors in theFR BOG response.Methods We examined
FR BOG responses insig mutants, phytochrome‐deficient lines, and mutant lines for several phy‐associated factors. We quantified chlorophyll levels and examined expression of keyBOG ‐associated genes.Results Among six
sig mutants, only thesig6 mutant significantly accumulated chlorophyll afterFR BOG treatment, similar to thephyA mutant.SIG 6 appears to control protochlorophyllide accumulation by contributing to the regulation of tetrapyrrole biosynthesis associated with glutamyl‐tRNA reductase (HEMA 1) function, select phytochrome‐interacting factor genes (PIF4 andPIF6 ), andPENTA1 , which regulatesPORA mRNA translation afterFR exposure.Conclusions Regulation of
SIG6 plays a significant role in plant responses toFR exposure during theBOG response.
