Pod Shattering Research Articles

NAC transcription factors NST1 and NST3 regulate pod shattering in a partially redundant manner by promoting secondary wall formation after the establishment of tissue identity

Three distinct pattern elements of the silique are thought to contribute to its dehiscence: a separation layer, cells with a secondary wall adjacent to the separation layer, and a valve endocarp layer with secondary wall. However, the role of the secondary wall has not been proven, and the factors that regulate its formation in siliques remain to be characterized. We show here that secondary wall formation in siliques is necessary for dehiscence, and that two plant-specific transcription factors, NAC SECONDARY WALL THICKENING PROMOTING FACTOR 1 and 3 (NST1 and NST3), regulate its formation in siliques of Arabidopsis. The promoters of the NST1 and NST3 genes were active in the valve endocarp layer and in cells surrounding vascular vessels in the replum, and NST1 promoter activity only was faintly detectable at valve margins. In nst1 mutants, specific loss of secondary walls was evident at valve margins, while nst1 nst3 double mutants lacked secondary walls in all parts of the siliques, with the exception of vascular vessels. These siliques were similarly indehiscent. The promoters of two tissue-identity genes, INDEHISCENT (IND) and SHATTERPROOF2 (SHP2), were as active in the nst1 nst3 mutant as in the wild-type. Moreover, the ectopic secondary wall formation that occurs in the fruitfull (ful) mutant was absent in the ful nst1 double mutant. We propose that secondary walls in valve margins are required for dehiscence, and that NST1 and NST3 regulate their formation in siliques in a partially redundant manner after the establishment of tissue identity.

Development of sequence-specific PCR markers linked to the Tardus gene that reduces pod shattering in narrow-leafed lupin (Lupinus angustifolius L.)

Seed pods of wild-type narrow-leafed lupins (Lupinus angustifolius L.) shatter upon maturity, dispersing their seeds. Recessive alleles of the genes Tardus and Lentus that confer reduced pod shattering have been incorporated into domesticated cultivars to facilitate harvesting. Tardus was mapped in an F8 recombinant inbred population of a cross between domesticated and wild lupins. A microsatellite–anchored fragment length polymorphism marker (TaM1), which mapped 2.1 cM from Tardus, was converted to a locus-specific PCR assay. Marker TaM2, a restriction fragment length polymorphism marker was converted to a PCR assay and mapped to 3.9 cM on the other side of Tardus. Marker TaM3, a cleaved amplified polymorphic sequence marker, was positioned along-side marker TaM1 at 3.9 cM from Tardus. One or more markers was polymorphic in 70% of possible pairwise crosses between Australian domesticated lines and wild accessions tested, indicating wide applicability of the markers in crosses between wild and domesticated germplasm.

Novel Nuclear Protein ALC‐INTERACTING PROTEIN1 is Expressed in Vascular and Mesocarp Cells inArabidopsis

Pod shattering is an agronomical trait that is a result of the coordinated action of cell differentiation and separation. In Arabidopsis, pod shattering is controlled by a complex genetic network in which ALCATRAZ (ALC), a member of the basic helix-loop-helix family, is critical for cell separation during fruit dehiscence. Herein, we report the identification of ALC-INTERACTING PROTEIN1 (ACI1) via the yeast two-hybrid screen. ACI1 encodes a nuclear protein with a lysine-rich domain and a C-terminal serine-rich domain. ACI1 is mainly expressed in the vascular system throughout the plant and mesocarp of the valve in siliques. Our data showed that ACI1 interacts strongly with the N-terminal portion of ALC in yeast cells and in plant cells in the nucleus as demonstrated by bimolecular fluorescence complementation assay. Both ACI1 and ALC share an overlapping expression pattern, suggesting that they likely function together in planta. However, no detectable phenotype was found in plants with reduced ACI1 expression by RNA interference technology, suggesting that ACI1 may be redundant. Taken together, these data indicate that ALC may interact with ACI1 and its homologs to control cell separation during fruit dehiscence in Arabidopsis.

Functional characterization and mapping of two MADS box genes from peach (Prunus persica)

Previously an AGAMOUS gene homologue PpMADS4 and a FRUITFULL gene homologue PpMADS6 were isolated from peach (Prunus persica), and both genes were shown to express in the developing floral and fruits. To gain insight into their function, the two genes were constitutively expressed in Arabidopsis thaliana and their effects on plant growth and floral organ development were studied in this work. The transgenic plants all displayed early flowering and conversion of inflorescence to floral meristem. However, the two genes had different effects on the floral organ structures in A. thaliana. The transgenic plants overexpressing PpMADS4 displayed homeotic conversion of floral organs, and particularly the perianth abscission was inhibited. The plants overexpressing PpMADS6 showed early flowering, produced higher number of carpels, petals, and stamens than nontransgenic plants, and pod shatter was prevented; significantly, the transgenic plants yielded more than one siliques from a single flower. A SSR molecular marker was developed for PpMADS4, and it was then assigned into the G5 linkage group of Prunus sp. Both PpMADS4 and PpMADS6 genes were located at the same region in the G5 linkage group. Our results showed the potential application of these two MADS box genes for crop and fruit tree improvement.

Assessment of seed shattering resistance and yield loss in five oilseed crops

Use of appropriate harvest management can minimize the yield loss of crucifer crops due to seed and pod shattering. This study determined the difference among five canola/mustard species in the degree of resistance to seed shattering and yield losses. Sinapis alba yellow mustard AC Base, Brassica juncea canola Amulet, Brassica juncea mustard Cutlass, Brassica rapa canola Hysyn, and Brassica napus canola InVigor 2663 were grown at Star City, Scott and Swift Current, SK, from 2004 to 2006. Seed yield was highest for napus canola (2146 kg ha-1), followed by juncea mustard (1971 kg ha-1) and juncea and rapa canola, while alba mustard (1547 kg ha-1) was the lowest. Straight combining compared with swathing resulted in 13% greater seed yield for juncea canola and juncea mustard, and 7% greater for rapa canola, while napus canola did not show yield difference between the two operation regimes. Under high shattering conditions, juncea mustard shed about 400 pods m-2, significantly greater than the four other species. Rapa canola had the lowest number of shed pods. Juncea mustard and napus canola had largest yield loss (about 7% of the total seed yield) during straight combining, followed by alba mustard (5%), and rapa and juncea canola (< 4%). Selection of shattering resistant species and use of straight combining can minimize seed yield losses in the production of crucifer oilseed crops. Key words: Brassica napus, Brassica rapa, Brassica juncea, Sinapis alba, swathing, straight–combine

참깨 탈립 작업기계 개발에 관한 연구(I) - 시작기 설계 제작 -

Sesame has usually been harvested manually in korea. The conventional sesame harvest procedures consists of cutting, binding, drying and pod shattering. The procedures of drying and shattering are repeated <TEX>$2{\sim}3$</TEX> times. By manual works of this conventional shattering, it was found that some extent of pods were has always remained unopened. Therefore, this study was conducted to find a way to save the labor of sesame shattering by use of a drying device; a prototype of shattering machine was developed and tested the performance. The developed prototype consists of several parts: a continuous horizontal inlet using a chain conveyer, a shattering by a shocking agitator, a rotating cone for shattering of remaining closed pods, and a winnow. The shattering ratio measured by this prototype was 90.3%, 6.4% and 3.3% at the first, second and third shattering step, respectively. We found that in contrast to the conventional method which required at least 3 times operations for complete shattering, this shattering prototype with the condition of sufficient dried sesame pod offered more than 90% of shattering ratio in the first operation.

Pod shatter resistance evaluation in cultivars and breeding lines of Brassica napus, B. juncea and Sinapis alba

AbstractPod shatter susceptibility was investigated in Brassica napus germplasm and shatter resistant species of B. juncea and Sinapis alba. The comparisons were made by measuring seed yield in field plots, detached pod rupture energy (RE) and the half‐life of pod‐opening. Pod shatter resistance was significantly greater in B. napus lines derived from interspecific hybridizations of B. napus with B. rapa, B. carinata and B. juncea, than common B. napus cultivars. While these lines exhibited no significant difference in resistance to pod shatter than B. juncea, an entry of S. alba had no yield loss caused by pod shatter. Resistance to pod shatter was characterized in the field as little or no yield loss after full maturity, delayed shattering in time, and stable yield performance under variable climatic conditions during pod maturity. Yield loss caused by pod shatter ranged from a low of 4% for the B. juncea cv. ‘AC Vulcan’ to a high of 61% for the black seeded B. napus line DH12075 in 2‐year field trials after 1 month maturity. Pod shatter resistance was not significantly associated with specific plant and pod morphological traits, except pod length (P = 0.005) in tested materials. Field visual scores of pod shatter through inspections of average pod shatter per plant within plots were highly correlated with plot yield loss. Indoor quantitative evaluations of pod strength using a pendulum machine to measure pod RE and random impact test to measure half‐life of pod‐opening resistance were highly correlated with field yield loss. Multiple evaluations of pod shatter in method and in time after pod maturity are recommended for reliable evaluation of pod shatter resistance.

Effect of Harvest Timing on Yield and Mineral Nutritional Value of Kabuli Type Chickpea Seeds

ABSTRACT Chickpea (Cicer arietinum L.) seeds are a good source of protein and mineral nutrients. However, there is no information regarding harvest timing on yield and mineral composition of chickpea seeds. The effect of harvest timing on seed yield, some yield components and mineral nutritional value of seeds of field grown chickpea plants in two different sites were studied. The mineral composition of chickpea straw depending on harvest timing was also evaluated in order to explain the variations of seed mineral concentrations in sink-source relationship manner. Yield and mineral nutritional value of chickpea were significantly affected by harvest timing. When compared to the seed yield at optimal harvest time, seed yield was 18% and 9% lower in the early harvest and 27% and 31% in the late harvest in Site 1 and Site 2, respectively. Late harvest of chickpea crops resulted in significant pod dropping and shattering. Generally, protein, phosphorus (P), calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), and manganese (Mn) concentrations of the seeds in optimal harvest were found to be greater than in early and late harvested plants. Harvest timing also results in significant variations in straw mineral nutrient concentrations of the plants. As the results of this study, it was concluded that the harvest timing is critical for yield losses and mineral nutritional value of chickpea seeds.

Characterization and expression analysis of FRUITFULL- and SHATTERPROOF-like genes from peach (Prunus persica) and their role in split-pit formation

The fruit canning industry processes large quantities of the clingstone varieties of peach (Prunus persica L. Batch). The occurrence of split-pit formation--the opening of the pit and sometimes splitting of the fruit--causes deterioration of canned fruit quality. The frequency of split-pit formation is influenced by genetic and environmental factors. To increase understanding of the molecular mechanisms underlying split-pit formation in peach, we cloned and characterized the PPERFUL and PPERSHP genes that are homologues to the genes FRUITFULL and SHATTERPROOF, respectively, which are involved in fruit splitting (pod shattering) in Arabidopsis thaliana. The deduced amino acid sequences of the two genes had high homology with members of the MADS-box family of transcription factors, and particularly with other members of the FUL-like family of A-type MADS-box proteins and PLENA-like family of C-type MADS-box proteins, respectively. PPERFUL and PPERSHP were expressed throughout fruit development from full anthesis until fruit harvest. Differences in the mRNA abundance of each gene were compared in a split-pit sensitive and a split-pit resistant variety. Results suggested that temporal regulation of PPERFUL and PPERSHP expression may have an effect on the split-pit process.

UFUS-Imperial: nova cultivar de soja para o Estado de Mato Grosso

A fim de ampliar as opções ao cultivo da soja, a Universidade Federal de Uberlândia lançou a cultivar UFUS-Imperial, proveniente do cruzamento entre (Msoy 8411xMsoy 8914) x (Emgopa 313xTucano). A cultivar apresentou resistência ao acamamento, à deiscência da vagem e aos patógenos: Fusarium solani, Cercospora sojina, Peronospora manshurica, Xanthomonas campestris pv. glycines e Diaporthe phaseolorum f.sp. meridionalis, e resistência parcial a Septoria glycines, Erysiphe diffusa e Phakopsora pachyrhizi. O rendimento dessa cultivar, em ensaios regionais, foi 45% superior ao da testemunha Msoy 6101, e é indicada para o Estado de Mato Grosso.

Development of two sequence-specific PCR markers linked to the le gene that reduces pod shattering in narrow-leafed Lupin (Lupinus angustifolius L.)

Wild types of narrow-leaf lupin (Lupinus angustifolius L.) have seed pods that shatter upon maturity, leading to the loss of their seeds before or during the harvest process. Two recessive genes have been incorporated into domesticated cultivars of this species to maximize harvest-ability of the produce. One of these genes is called lentus (le). Two microsatellite - anchored fragment length polymorphism (MFLP) candidate markers were identified as closely linked to the le gene in a recombinant inbred line (RIL) population derived from a domesticated x wild type cross. The candidate MFLP markers were isolated from the gel, re-amplified by PCR, cloned and sequenced. The MFLP polymorphisms were converted into sequence-specific PCR-based markers. Linkage analysis by MapManager indicated that one of the markers, LeM1, was 2.6 centiMorgans (cM) and the other, LeM2, was 1.3 cM from the gene, with both being on the same side. The correlation between the marker genotype and the plant phenotype for the le gene is 95% for the Australian cultivars, and approximately 36% on wild types tested. These markers may be useful in marker assisted selection for the le gene when introgressing wild material into lupin breeding programs.

Plant translational genomics: from model species to crops

Plant genomic research now faces the ultimate challenge to develop applications in crop plants which implies the translation of gene functions from a model to a crop which is the field of ‘Plant translational genomics’. In this paper we discuss the perspectives of the candidate gene approach (CGA) as a tool for translational genomics in the ‘whole genome’ era. Factors to be considered for a successful application of the CGA in crops such as the type of crop, the complexity of the trait and the type of genes involved are discussed. Several crop traits that require improvement such as tolerance to stress, pod shatter in Brassicaceae and Fusarium resistance, are evaluated with regard to the potential of a CGA as a tool for crop improvement

`Golden Eye Cream': A Large-seeded, High-yielding, Early-maturing Southernpea for the Fresh Market and Home Garden

Golden Eye Cream is a unique, largeseeded, cream-type southernpea [Vigna unguiculata (L.) Walp.] released by the Texas Agricultural Experiment Station in 2006. The name describes the appearance of the pea. It was developed for the fresh market and home garden trades possibly to replace some of the small-seeded creams. It does not appear to be suitable for canning. Generally, Golden Eye Cream matures at least 10 d earlier than White Acre and about the same or slightly earlier than Early Acre and is higher yielding than both, especially at narrow-row spacing. Golden Eye Cream consistently produces a higher percent shell-out (66% to 69%) than White Acre or Early Acre . It exhibits a high level of resistance to root knot nematode. Golden Eye Cream resists lodging and pod shattering.

Simple sequence repeat markers linked to a major QTL controlling pod shattering in soybean

AbstractShattering of soybean pods prior to harvest leads to a reduction in yield. In order to identify simple sequence repeat (SSR) markers linked to quantitative trait loci (QTLs) conditioning pod shattering, QTL analysis was conducted using an recombinant inbred line (RIL) population segregating for this trait. The degrees of pod‐shattering resistance were evaluated by heat treatment applied to pods harvested from plants in the field and in a growth chamber. Composite interval mapping identified one major QTL between SSR markers Sat_093 and Sat_366 on linkage group J for both environments. The position and the effect of this QTL were confirmed in an F2 population derived from a cross between the pod shattering‐susceptible parental cultivar and a pod shattering‐resistant RIL. The SSR markers linked to the major QTL will be useful for marker‐assisted selection in soybean‐breeding programmes.

Effects of Some Plant Growth Regulators and Nutrient Complexes on Pod Shattering and Yield Losses of Soybean under Hot and Dry Conditions

Effects of Some Plant Growth Regulators and Nutrient Complexes on Pod Shattering and Yield Losses of Soybean under Hot and Dry Conditions

Pod shatter‐resistant Brassica fruit produced by ectopic expression of the FRUITFULL gene

Arabidopsis has proven to be extremely useful as a reference organism for studies in plant biology, and huge efforts have been employed to unravel various mechanisms of Arabidopsis growth. A major challenge now is to demonstrate that this wealth of knowledge can be used for global agricultural and environmental improvement. Brassica species are closely related to Arabidopsis and represent ideal candidates for model-to-crop approaches as they include important crop plants, such as canola. Brassica plants normally disperse their seeds by a pod-shattering mechanism. Although this mechanism is an advantage in nature, unsynchronized pod shatter constitutes one of the biggest problems for canola farmers. Here, we show that ectopic expression of the Arabidopsis FRUITFULL gene in Brassica juncea is sufficient to produce pod shatter-resistant Brassica fruit and that the genetic pathway leading to valve margin specification is conserved between Arabidopsis and Brassica. These studies demonstrate a genetic strategy for the control of seed dispersal that should be generally applicable to diverse Brassica crop species to reduce seed loss.

Modulating flowering time and prevention of pod shatter in oilseed rape

Floral induction is a key developmental switch in plants that leads to the production of flowers, fruits and seeds, which are of paramount importance for human life. To meet the demands of several crop harvests per year, or the growth of crop plants in regions with short vegetation times and for the production of ornamental plants, the timing of the floral transition is very important. The discovery of genes that are involved in flowering time control in model plants should allow the modulation of this developmental switch also in plants with economic value. By using a transgenic approach, we showed that a single MADS box gene accelerated flowering and seed ripening in summer rape plants. The MADSB transgene also partially substituted for the strict temperature requirements for flowering in winter rape plants. Transgenic winter rape plants expressing the MADSB transgene also produced more rigid siliques than wild type winter rape plants, and this prevented precocious seed dispersal.

The Gene slm1-1 Regulates Abscission, Dehiscence, Meristem Arrest, and Apical Dominance in Arabidopsis thaliana

Cell separation regulates basic developmental processes such as abscission and dehiscence and is one of the horticultural traits first to be selected by mankind. Abscission is characterized by an active cell separation process where organs are detached from the main body of the plant through the dissolution of the middle lamella. Crops with early abscission can have significant reduction in yield. For example, canola, Brassica napus, loses 5% to 10% of crop due to early pod shatter. By screening T-DNA mutagenized populations of A. thaliana for delayed abscission, we have identified several genes that regulate cell separation, slm1-1 (slender lasting inflorescence and meristem) is one such genes. During our investigation of slm1-1 we have employed phenotypic, physiological, genetic, and molecular assays. Phenotypically, slm1-1 displays traits such as delayed abscission of floral organs, lack of anther pollen dehiscence (making slm1-1 functionally male sterile), delayed meristem arrest, and strong apical dominance. Phenotypic characterization includes scanning electron microscopy, bright field microscopy, and stereoscope microscopy. Physiological assays include reporter gene expression and break strength analyses. Genetically, slm1-1 is regulated by a single recessive gene. Molecular assays characterizing slm1-1 include TAIL-PCR, RT-PCR, and preliminary microarray of abscission zones. We have also begun to map based cloning of slm1-1. We believe that understanding genes that regulate cell separation in A. thaliana will contribute to crop improvement. Applications could include reducing loss during harvesting, regulation of pollination, changes in branching patterns, and longevity of flowering.

Control of Fruit Patterning in Arabidopsis by INDEHISCENT

The Arabidopsis seedpod opens through a spring-loaded mechanism known as pod shatter, which is essential for dispersal of the seeds. Here, we identify INDEHISCENT (IND), an atypical bHLH protein, that is necessary for fruit opening and is involved in patterning each of the three fruit cell types required for seed dispersal. Previous studies suggested that FRUITFULL (FUL), a member of the MADS-domain transcription factor family, is required for fruit growth since ful mutant fruit fail to undergo the dramatic enlargement that normally occurs after fertilization. Here we show, however, that FUL is not directly required for fruit elongation and instead is required to prevent ectopic activity of IND. Our molecular and genetic studies suggest a model for the regulatory interactions among the genes that control fruit development and the mechanism that results in the expression of IND in a narrow stripe of cells.

Effect of maturity stage on germination and dormancy of fresh and air‐dried seeds of bitter vetch (Vicia ervilia L.)

Bitter vetch is an important legume crop cultivated for forage and seed yield in the Mediterranean, West Asia, and North Africa regions. Delaying seed harvest of bitter vetch may increase seed losses due to pod shattering; however, early harvest may influence seed dormancy and the ability of seed to germinate. Field experiments were conducted at two locations in Jordan to study the effect of maturity stage on germination and dormancy of fresh (before drying), air‐dried, and dry‐prechilled (at 5°C for 8 days) seeds of bitter vetch. Pods were harvested at three development stages: full‐seed pod (FS), yellow pod (YP), and brown pod (BP). Percentage of normal, abnormal, hard, and dead seeds at 14 days after planting in standard germination tests was recorded for the fresh, air‐dried, and dry‐prechilled seeds harvested at the three development stages. Germination counts of normal seedlings at 4, 7, 10, and 14 days after planting was used to calculate the germination rate index (GRI). For the fresh seeds, germination did not exceed 30% when seeds were harvested at the FS stage, and decreased to 0% at the YP stage. All non‐germinated fresh seeds harvested at the YP stage were dormant. Air‐drying and dry‐prechilling treatments improved seed germination at the YP and BP stages. Maximum germination was achieved in air‐dried and dry‐prechilled seeds harvested at the BP stage. The percentage of hard seeds was the highest for air‐dried seeds harvested at the FS stage. Percentage of hard and dormant seeds was decreased to the minimum when seeds were harvested at the BP stage and exposed to air‐drying and dry‐prechilling treatment before germination. Dry‐prechilled seeds had higher GRI than fresh and air‐dried seeds when seeds were harvested at the BP stage. In conclusion, maximum germination and minimum dormancy was achieved for air‐dried and dry‐prechilled seeds harvested at the BP stage. Dry‐prechilling treatment increased the speed of germination for seeds harvested at the BP stage. Presence of hard seeds reduced the germination of air‐dried seeds harvested at the YP stage. Bitter vetch seeds harvested at the YP stage may require scarification and a longer prechilling treatment to overcome seed dormancy observed at this stage.