Gene expression profiling of the green seed problem in Soybean

Abstract

BackgroundDue to the climate change of the past few decades, some agricultural areas in the world are now experiencing new climatic extremes. For soybean, high temperatures and drought stress can potentially lead to the “green seed problem”, which is characterized by chlorophyll retention in mature seeds and is associated with lower oil and seed quality, thus negatively impacting the production of soybean seeds.ResultsHere we show that heat and drought stress result in a “mild” stay-green phenotype and impaired expression of the STAY-GREEN 1 and STAY-GREEN 2 (D1, D2), PHEOPHORBIDASE 2 (PPH2) and NON-YELLOW COLORING 1 (NYC1_1) genes in soybean seeds of a susceptible soybean cultivar. We suggest that the higher expression of these genes in fully mature seeds of a tolerant cultivar allows these seeds to cope with stressful conditions and complete chlorophyll degradation.ConclusionsThe gene expression results obtained in this study represent a significant advance in understanding chlorophyll retention in mature soybean seeds produced under stressful conditions. This will open new research possibilities towards finding molecular markers for breeding programs to produce cultivars which are less susceptible to chlorophyll retention under the hot and dry climate conditions which are increasingly common in the largest soybean production areas of the world.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0729-0) contains supplementary material, which is available to authorized users.

ABI5 Is a Regulator of Seed Maturation and Longevity in Legumes

“…(2) downregulation of expression of photosynthesis-associated nuclear genes, which is accompanied by chlorophyll and carotenoid degradation (although probably not directly regulated by ABI5) and leads to chloroplast dedifferentiation, which altogether prevents oxidative stress in the mature seed; and (3) induced expression of SIP1, thus producing RFO, which might inhibit oxidative stress both inside and outside the chloroplast. Thus, ABI5 appears to be a prominent regulator of late maturation in legumes, and this finding sheds light on the relationship between seed vigor and RFO accumulation (Vandecasteele et al, 2011) and chlorophyll retention (Jalink et al, 1998;Nakajima et al, 2012;Delmas et al, 2013;Teixeira et al, 2016). Together with previous studies showing a correlation between longevity and chlorophyll retention in Arabidopsis (Clerkx et al, 2003;Nakajima et al, 2012), our data suggest that degreening cannot be uncoupled from longterm survival in the dry state, an important aspect of seed vigor and seedling establishment.…”

“…In oily non-chlorophyllous seeds, the presence of chlorophyll in mature seeds is an undesirable trait leading to poor nutritional quality, reduced longevity and economic losses (Jalink et al, 1998;Clerkx et al, 2003;Chung et al, 2006;Nakajima et al, 2012;Delmas et al, 2013;Teixeira et al, 2016). Although the link between chlorophyll retention and poor seed quality has been suggested for a long time, a direct cause-effect relationship with longevity has been established only recently.…”

“…In most plant species, chlorophyll is degraded during the late stages of seed maturation, before the seed reaches the dry state (Nakajima et al, 2012;Delmas et al, 2013;Teixeira et al, 2016). Chlorophyll retention in dry oily seeds appears to be detrimental to seed longevity.…”

Effect of Water Deficit-Induced at Vegetative and Reproductive Stages on Protein and Oil Content in Soybean Grains

“…Although protein content in soybean grains increased under WD, the physicochemical quality of grains can be impaired under severe drought conditions. Under WD, a larger number of green grains were detected in soybean lots [31], increasing the acidity level of the grains. Crude oil obtained from such grains has a green color with a high free fatty acid content [32].…”

Integrated “omics” approaches to sustain global productivity of major grain legumes under heat stress

“…Furthermore, reduction in germination percentage and vigour of harvested seeds (average seed weight) under HS was investigated by Dornbos and Mullen (). Moreover, quality of soybean seed deteriorates due to retaining chlorophyll in mature seed known as “green seed problem” under HS (Teixeira, Ligterink, França‐Neto‐Jde, Hilhorst, & da Silva, ). Importantly, under high root temperature, nitrogen‐fixing bacterial infection is severely affected (Munevar & Wollum, ).…”